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THE  UNIVERSITY 

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ILLINOIS  BIOLOGICAL 
MONOGRAPHS 


PUBLISHED  QUARTERLY 

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BY  THE  UNIVERSITY  OF  ILLINOIS 


VOLUME  II 


Urbana,  Illinois 
1915-16 


Editorial  Committee 


Stephen  Alfred  Forbes  William  Trelease 

Henry  Baldwin  Ward 


T 


TABLE  OF  CONTENTS 

Volume  II 


NUMBERS  PAGES 

I        The    Classification    of    Lepidopterous    Larvae.      By    Stanley    Black 

Fracker.    With  lo  plates 1-170 


(Distributed  October  5,  1915) 


2        On  the  Osteology  of  Some  of  the  Loricati.    By  John  Earl  Gutberlet. 

With  5  plates 171-210 

(Distributed  February  25,  1916) 


Studies  on  Gregarines,  Including  Descriptions  of  Twenty-one  New 
Species  and  a  Synopsis  of  the  Eugregarine  Records  from  the 
Myriapoda,  Coleoptera  and  Orthoptera  of  the  World.  By  Minnie 
Elizabeth  Watson.     With   15  plates 211-468 

(Distributed  June  29,  1916) 


The  Genus  Meliola  in  Porto  Rico,  Including  Descriptions  of  Sixty-two 
New  Species  and  Varieties  and  a  Synopsis  of  all  Known  Porto 
Rican  Forms.     By  Frank  Lincoln  Stevens.    With  5  plates 469-554 

(Distributed  June  30,  1916) 


^^^rki-\^%  i-v, 


ILLINOIS    BIOLOGICAL 
MONOGRAPHS 

Vol.  II  July.  1915  N( 


THE  CLASSIFICATION  OF   LEPIDOPTEROUS   LAK 


WITH  TKN   Pr.ATliS 


BV 


STANLEY  BLACK  FRACKER 


PRICE    SI.SO 


PUBLISHED  BY  THE  UNIVERSITY  OF  ILLINOIS 

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P 


ILLINOIS  BIOLOGICAL 
MONOGRAPHS 


Vol.  II  July.  1915  No.  I 


Editorial  Committee 


Stephen  Alfred  Forbes  William  Trelease 

Henry  Baldwin  Ward 


Published  under  the 

Auspices  of  the  Graduate  School  by 

THE  University  of  Illinois 


Copyright,  1915 
By  the  University  of  Illinois 

Distributed  October  5,  1915. 


THE  CLASSIFICATION   OF 
LEPIDOPTEROUS  LARVAE 


WITH  TEN  PLATES 


BY 


STANLEY  BLACK  FRACKER 


Contributions  from  the 

Entomological   Laboratories  of  the   Universitity   of   Illinois 

No.   43. 


THESIS 

Submitted  in  Partial  Fulfilment  of  the  Requirements 

for  the   Degree   of  Doctor  of  Philosophy  in 

Entomology  in  the  Graduate  School 

of  the  Linivtrsity  of  Illinois 

1914 


TABLE  OF  CONTENTS 


PAGE 

Acknowledgments 9 

PART  ONE.    THE  HOMOLOGY  OF  THE  SETAE. 

I.  Introduction    ii 

Historical   12 

The  Chaetotaxy  of  a  Typical  Segment 14 

II.  Nature   of   the  Evidence .14 

Definitions    15 

Difficulties  15 

Comparative  Anatomy 17 

Ontogeny  17 

Variation    20 

III.  Application  of  the  Evidence 20 

Application  of  Principles  21 

Choice  of  a  Nomenclature 22 

IV.  Setal  arrangement  in  the  Principal  Superfamilies  23 

S  uborder  Jugatae  24 

First  Instar  24 

Later  In  stars  25 

Conclusions  from  a  Study  of  Jugatae 29 

Suborder  Frenatae 29 

V.  Primary  and  Subprimary  Setae 32 

Alpha,  32;   Beta,  32;   Gamma,  33;  Delta,  33;   Epsilon,  33;   Rho,  34; 
Theta,  34;  Kappa,  35;  Eta,  35;  Pi,  36;  Mu,  37;  Sigma,  38;  Tau,  38. 

VI.  General  Conclusions  38 

Synonyms  39 

PART  TWO.    SYSTEMATIC  OUTLINE  OF  FAMILIES  AND  GENERA 

Introduction  41 

Characters  Used  42 

Head  Parts,  43;  Armature  of  the  body,  44;  Spiracles,  45;  Prolegs,  45; 
Other  Structures,  47. 


ILLINOIS    BIOLOGICAL    MONOGRAPHS  [6 

PAGE 

Classification    '. 48 

Analytical  Table  of  Families 49 

Suborder  Jugatae 60 

Micropterygoidea   60 

Hepialidae    60 

Micropterygidae  60 

Suborder  Frenatae  61 

Microlepidoptera  61 

Aculeata    62 

Nepticulidae  64 

Prodoxidae  64 

Incurvariidae  65 

Tischeriidae  66 

Non-aculeata   62 

Tineoid  series  66 

Tineoidea   „ 66 

Acrolophidae 66 

Tineidae    67 

Bucculatrigidae  67 

Lyonetiidae    67 

Yponomeutoidea  68 

Helipdinidae  68 

Yponomeutidae  69 

Gracilariidae 70 

Tortricidae 71 

Thyrididae   74 

Aegeriidae    „ 75 

Cossidae    77 

Psychidae 78 

Elachistidae   80 

Coleophoridae   80 

Gelechioidea  80 

Ethmiidae  81 

Stenomidae  , 81 

Hemerophilidae  82 

Gelechiidae  83 

Oecophoridae  85 

Blastobasidae  86 

Cosmopterygidae 86 

Pyrali-zygaenoid   series  86 

Pyralidoidea  86 

Pyralididae  87 

Orneodidae  94 

Pterophoridae   94 


7]  LEPIDOPTEROUS   LARVAE— FR ACKER  7 

PAGE 

Zygaenoidea  95 

Chalcosidae  95 

Dalceridae  95 

Pyromorphidae   95 

Epipyropidae 96 

Megalopygidae 96 

Cochlidiidae   97 

Lacosomidae    « 98 

NoHdae   98 

Macroheterocera  100 

Bombycoidea   100 

Epiplemidae   100 

Geometridae  icx) 

Platypterygidae  .-. lOi 

Bombycidae 102 

Lasiocampidae  102 

Eupterotidae 103 

Liparidae  104 

Thyatiridae    106 

Notodontidae  106 

Dioptidae no 

Pericopidae  Hi 

Nycteolidae in 

Noctuidae  in 

Agaristidae  114 

Arctiidae  114 

Lithosiidae 118 

Syntomidae  118 

Saturnioidea  120 

Ceratocampidae  121 

Hemileucidae  121 

Saturniidae  _ 121 

Sphingoidea   126 

Sphingidae    126 

Rhopalocera  126 

Hesperioidea 127 

Hesperiidae 127 

Megathymidae  128 

Lycaenoidea  128 

Lycaenidae   128 

Riodinidae : - 129 

Nymphaloidea   130 

Libytheidae  130 

Lymnadidae   130 

Ithomiidae 130 

Heliconiidae  131 

Agapetidae   131 

Nymphalidae   132 


8  ILLINOIS    BIOLOGICAL   MONOGRAPHS  [8 

PAGE 

Papilionoidea  136 

Pieridae  136 

Papilionidae  138 

Parnassiidae  140 

Glossary 141 

Bibliography 145 

Explanation  of  Plates 147 

Index   165 


9]  LEPIDOPTEROUS    LARVAE  — FRACKER 


ACKNOWLEDGMENTS 

The  subject  of  this  paper  was  suggested  by  Professor  Alexander 
D.  MacGillivray  in  the  fall  of  1912.  During  the  two  years  since  that 
time  the  writer  has  become  more  and  more  convinced  of  the  necessity 
for  and  value  of  taxonomic  studies  of  immature  insects.  While  a  classi- 
fication based  on  larvae  would  doubtless  include  as  serious  mistakes  as 
one  in  which  only  the  adults  were  considered,  combining  the  two  methods 
results  in  the  elimination  of  a  great  many  errors.  In  addition  to  this 
purely  scientific  ideal,  the  demand  of  students  and  economic  entomolo- 
gists for  some  means  of  identifying  larvae  without  rearing  them  has 
acted  as  an  even  stronger  incentive  to  persistent  eifort. 

The  author  wishes  to  express  his  sincere  appreciation  of  the  sugges- 
tions and  criticisms  of  Professor  MacGillivray  throughout  the  prepar- 
ation of  the  paper  and  of  the  inspiration  which  has  come  from  association 
with  him.  The  authorities  of  the  University  of  Illinois  have,  through 
liberal  appropriation,  made  possible  the  purchase  of  material  from 
Dr.  0.  Staudinger  and  A.  Bang-Haas  of  Dresden,  from  the  Kny-Scheerer 
Company,  from  the  Ward  Natural  Science  Establishment,  and  from 
Mr.  Wm.  Beutenmiiller.  They  have  also  enabled  the  writer  to  study 
for  several  months  at  the  United  States  National  Museum,  where  the 
series  of  lepidopterous  larvae  is  probably  the  most  extensive  in  the 
world.  For  securing  this  assistance,  for  continuous  encouragement,  and 
for  placing  at  his  disposal  the  material  of  the  Illinois  State  Laboratory  of 
Natural  History,  the  author  gives  hearty  thanks  to  Professor  Stephen 
A.  Forbes.  Grateful  acknowledgments  are  due  Dr.  L.  0.  Howard 
for  his  courtesy  in  granting  use  of  the  entomological  collections  of  the 
National  Museum.  To  Dr.  Harrison  G.  Dyar,  Mr.  August  Busck,  and 
Mr.  Carl  Heinrich,  the  writer  is  indebted  for  numerous  suggestions  and 
for  making  these  collections  accessible  and  helpful. 


11]  LEPIDOPTEROUS    LARVAE  — FR ACKER  11 


PART  ONE.    THE  HOMOLOGY  OF  THE  SETAE 


I.    Introduction 

One  of  the  most  serious  difficulties  in  the  path  of  scientific  progress 
is  the  lack  of  a  means  of  expression  common  to  all  the  workers  in  a  single 
field.  When  a  particular  term  means  one  thing  to  one  scientist  and 
something  else  to  another,  no  amount  of  learning  will  make  the  opinions 
of  these  men  intelligible  to  each  other  until  they  understand  the  differ- 
ence. In  human  anatomy,  the  large  number  of  workers,  the  excellent 
figures,  and  the  antiquity  and  narrow  limits  of  the  subject  have  to  a 
large  extent  removed  this  confusion  but  in  other  fields  of  biology  the 
mistakes  it  causes  are  still  apparent.  This  is  true  in  entomology  and 
very  noticeably  so  in  the  study  of  larvae. 

The  various  systems  of  numerals  which  have  been  applied  to  the 
setal  arrangement  of  lepidopterous  larvae  are  all  based  on  the  simple 
plan  of  numbering  the  setae  from  the  dorsomeson.  Except  in  the  most 
conspicuous  cases,  little  consideration  is  taken  of  the  relations  of  the 
different  segments  to  each  other.  Several  authors  have  already  intro- 
duced confusion  by  applying  the  numbers  in  a  slightly  different  way 
from  that  first  suggested,  but  no  careful  investigation  has  been  made 
of  the  real  relations  of  the  larval  chaetotaxy  of  one  group  to  that  of 
another. 

Realizing  the  conflicts  in  the  application  of  the  numerals  now  in  use 
and  the  nature  of  the  objections  to  them,  the  writer  began  the  study 
of  caterpillars  with  an  investigation  of  the  homology  and  homotypy  of 
the  setae.  The  object  of  the  former  was  a  determination  of  the  changes 
which  have  taken  place  in  the  ancestral  history  of  any  particular  body 
segment,  such  as  the  prothorax,  and  the  application  of  a  given  name  to 
the  same  structure  throughout  the  entire  order.  The  study  of  the  latter, 
homotypy,  was  taken  up  for  the  purpose  of  finding  the  relation  of  the 
setal  pattern  of  the  different  body  segments  to  each  other,  in  the  hope 
of  applying  the  same  name  to  the  same  structure  throughout  the  entire 
body.  All  the  segments  behind,  but  not  including,  the  head  were  studied 
and  satisfactory  results  were  obtained  for  all  except  the  tenth  or  last 
abdominal  segment. 


12  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [12 

It  is  intended  that  the  figures,  descriptions,  and  definitions  shall 
make  every  statement  in  this  paper  absolutely  definite  and  that  they 
shall  be  so  clear  that  a  novice  may  be  able  to  make  a  complete  description 
of  a  caterpillar  without  the  possibility  of  confusion  as  to  his  meaning. 
New  species  and  new  instars  should  be  described  in  a  manner  which 
will  make  like  specimens  recognizable  in  the  future  without  repeating  the 
breeding.  Such  complete  descriptions  in  the  published  records  are  very 
few  at  the  present  time. 

HISTORICAL 

The  first  worker  to  find  and  describe  a  primary  plan  of  the  setae  of 
caterpillars  was  Wilhelm  Miiller  (1886),  in  a  paper  on  the  Nymphalidae. 
After  discussing  the  arrangement  in  the  first  stage  of  these  butterfly 
larvae,  he  says :  * '  We  find  in  the  first  stage,  on  the  abdomen  of  all  forms 
considered,  certain  setae.  Tho  of  many  different  forms  their  constant 
arrangement  shows  them  to  be  homologous.  We  call  these  setae  pri- 
mary. *  *  Doubt  as  to  the  similarity  between  the  mesothorax  and 
metathorax  and  the  abdomen  seems  to  be  out  of  the  question."  In  an 
appendix,  brief  notes  on  the  chaetotaxy  of  the  larvae  of  other  families 
of  Lepidoptera  are  given.  Careful  comparison  is  made  between  the 
Saturnioidea  and  the  Sphingidae. 

Dr.  Harrison  G.  Dyar  did  not  find  this  paper  and  in  1894  again 
discussed  the  subject  as  new  and  numbered  the  primary  setae.  So  far 
as  I  know,  this  author  makes  the  first  suggestion  that  the  position 
of  the  setae  be  used  in  classification.  His  observations  included 
a  few  representatives  of  many  families  and  his  phylogeny  as 
based  on  them  is  remarkably  good.  He  also  numbers  the  metathoracic 
setae  but  makes  no  attempt  to  show  that  the  seta  bearing  a  certain  num- 
ber on  the  abdomen  is  homologous  with  one  bearing  the  same  number 
on  the  thora~.  He  himself  realized  that  the  metathoracic  ''tubercles," 
i  a-j-i  b  and  ii  a-^-ii^b  (Fig.  11),  were  not  the  homotypes  of  the  abdominal 
setae  i  and  ii  (Fig.  12),  and  in  1901  made  a  definite  statement  to  that 
effect.  This  discussion,  therefore,  can  not  be  considered  a  contribution 
to  the  study  of  homotypy. 

In  another  paper  the  following  year  the  same  author  reported 
observations  on  the  first  stages  of  many  larvae,  finding  that  they  dif- 
fered considerably  from  following  stages.  By  these  observations  he 
established  the  primary  arrangement  of  the  setae  on  the  abdomen  and 
demonstrated  its  uniformity  throughout  a  great  part  of  the  order.  A 
few  months  later,  in  "A  Classification  of  Lepidoptera  on  Larval  Char- 


13]  LEPIDOPTEROUS    LARVAE  — FRACKER  13 

acters",  he  made  the  former  work  on  the  Frenatae  apply  to  the  setal 
pattern  of  the  Jugatae.  The  purpose  of  this  paper  was,  however,  more 
to  point  out  the  differences  between  the  larvae  of  the  two  suborders  than 
to  show  their  similarity. 

0.  Hofmann  (1898)  described  the  first  and  later  instars  of  certain 
pterophorid  larvae,  reaching  the  conclusion  that  the  thoracic  and 
abdominal  setae  are  homologous  but  that  additional  ones  are  present  on 
the  prothorax.  The  suggestions  he  makes  and  the  reasons  given  are 
excellent.  Dyar's  nomenclature  is  used,  with  the  result  that  he  does 
not  make  his  own  conceptions  as  clear  as  if  he  had  changed  it  to  meet 
his  own  ideas  of  homology. 

In  response  to  criticism  by  Hofmann,  Dyar  (1901)  finally  did  ex- 
press an  opinion  on  the  serial  homology  of  the  setae  so  far  as  the  last 
two  thoracic  and  first  eight  abdominal  segments  are  concerned.  The 
table  he  gives,  which  is  as  follows,  merely  indicates  his  agreement  with 
the  views  of  Hofmann. 


Numerals  now  applied 

Should 

Thorax 

Abdomen 

be 

[  and  III 

1  to  8 

called 

i  a 

i 

i  b 

ii 

ii 

ii  a 

iii 

iii 

ii  b 

iv 

iv 

iii 

— 

V  a 

iv 

V 

V 

V 

vi 

V  b 

vi 

vii 

vi 

It  will  be  seen  that  the  conclusions  indicated  by  the  table  agree  in 
most  particulars  with  those  reached  on  later  pages  of  this  paper  except 
in  the  relation  of  setae  iv  and  v.  Altho  the  point  will  be  discussed  later, 
it  should  be  mentioned  here  that  the  error  arises  from  a  failure  to  consider 
the  condition  in  Hepialus.  The  larvae  of  that  genus  show  clearly  that 
the  missing  seta  near  the  abdominal  spiracle  is  not  between  iv  and  v 
but  above  iv.  Seta  iv  of  the  metathorax  is  therefore  homotypic  with  iv 
of  the  abdomen,  v  with  v  of  the  abdomen,  and  vi  of  the  abdomen  is  not 
represented  on  the  thorax.  Other  reasons  for  this  view  will  be  dis- 
cussed later. 

Ambrose  Quail  (1904)  discusses  these  particular  setae,  basing  his 
opinions  on  the  condition  in  the  first  instar  of  certain  Hepialidae  and 
Frenatae.  He  calls  attention  to  the  error  mentioned  above  and  shows 
Dyar's  mistake  concerning  the  true  meaning  of  iib.    Instead  of  being 


14  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [14 

homotypic  with  iv  of  the  abdomen,  it  is  shown  to  be  really  iii  a,  a  seta 
which  Dyar  had  either  overlooked  or  considered  of  no  importance. 

W.  T.  M.  Forbes'  work  (1910)  did  not  cover  the  subject  of  the 
homotypy  of  the  setae.  The  few  figures  he  labels  include  errors  for 
which  he  was  not  responsible  as  he  had  not  given  the  subject  con- 
sideration.    (See  discussion  of  theta,  page  34.) 

Siltala  (1907)  made  a  study  of  the  chitinous  armature,  especially 
the  setae,  of  caddice-worms.  He  finds  considerable  variation  in  the  order 
(Trichoptera)  but  carefully  compares  the  different  arrangements.  The 
setae  of  the  first  larval  stage  are  very  sparse  while  those  of  later  instars 
are  obviously  special  and  secondary  developments.  In  neither  case  can 
satisfactory  comparisons  be  made  with  the  Lepidoptera. 

THE  CHAETOTAXY  OF  A  TYPICAL  SEGMENT 

"While  previous  workers  have  drawn  so-called  type  segments,  these 
have  never  included  all  the  setae  found  in  larvae  of  this  order.  Their 
significance  has  been  limited  to  particular  segments  or  to  particular 
groups.  For  example,  Dyar's  ''typical  segment"  refers  to  the  abdomen 
only,  altho  it  has  been  extended  to  cover  the  last  two  thoracic  segments  of 
the  larvae  of  Frenatae. 

In  order  to  make  the  following  pages  clear,  attention  should  be 
called  at  this  point  to  the  diagram  (Fig.  1)  which  shows  all  the  pri- 
mary and  subprimary  setae  normally  present  on  the  segments  of  any 
generalized  lepidopterous  larva.  The  evidence  on  which  this  diagram  is 
based  and  also  the  reasons  for  the  adoption  of  Greek  letters  instead  of 
numerals  in  naming  the  setae  are  given  on  later  pages.  This  hypothetical 
type  is  mentioned  here  as  a  point  of  reference  in  order  that  it  may  be 
possible  to  use  the  setae  as  illustrations  of  the  general  principles  on 
which  this  study  of  homology  is  based.  On  the  same  and  the  follow- 
ing plates  are  shown  some  of  the  modifications  of  the  plan. 

It  has  been  necessary  to  introduce  certain  new  terms  in  this  paper 
and  in  a  few  cases  to  use  the  old  terms  in  a  special  sense.  A  glossary 
will  be  found  at  the  close  of  Part  Two,  giving  the  meaning  of  all  words 
used  in  a  special  sense  in  this  discussion.  The  explanation  of  plates 
(p.  147)  gives  the  names  and  grouping  of  all  the  setae. 

II.    Nature  op  the  Evidence 

It  is  necessary  first  to  outline  the  principles  underlying  attempts 
at  any  determination  of  homotypes.  The  evidence  on  which  decisions 
in  doubtful  cases  were  based  is  discussed  here,  for  some  of  the  principles 
are  not  axiomatic.  Their  correctness  will  not  be  disputed,  I  am  sure, 
by  those  who  consider  the  broad  basis  of  fact  on  which  they  rest. 


15]  LEPIDOPTEROUS    LARVAE  — FRACKER  15 

DEFINITIONS 

According  to  the  Standard  Dictionary,  homology  refers  either  (a) 
to  ' '  the  correspondence  of  a  part  of  one  animal  with  another,  determined 
by  agreement  in  derivation  and  development  from  a  like  primitive 
origin,"  or  (h)  to  homotypy,  which  is  'Hhe  correspondence  of  a  part  or 
organ  of  one  region  with  that  of  another  region  in  the  same  animal." 
Smith,  in  the  "Glossary  of  Entomology",  adds  the  usual  provision  that 
"the  organs  must  be  identical  in  general  structure  and  origin,  tho  they 
may  have  developed  in  different  ways  for  different  purposes. ' ' 

There  is  an  important  difference  between  the  homology  of  crustacean 
appendages  with  each  other  and  the  homology  of  the  setae  in  insects. 
In  the  former  case,  work  is  based  on  similarity  in  the  fundamental  struc- 
ture and  development  of  the  homologous  organs ;  in  the  latter,  only  pos- 
ition can  be  considered,  as  the  setae  are  all  similar  in  structure.  For 
that  reason  it  is  necessary  to  secure  a  little  more  accurate  definition  as  a 
basis  of  work.    With  this  in  view,  I  suggest  the  following: 

Two  organs  on  different  segments  of  the  same  animal  are  homotypic, 
regardless  of  their  positions  at  the  present  time,  when  they  have  developed 
from  homotypic  organs  of  a  generalized  ancestor.  In  a  generalized  type, 
two  similar  organs  on  different  segments  are  homotypes  when  they  'bear 
the  same  relations  to  the  other  orga7is  of  their  respective  segments. 

To  show  that  a  prothoracic  seta,  for  example,  is  homologous  with 
one  on  the  mesothorax,  it  is  necessary  to  show  that  at  one  time  the  anlagen 
from  which  these  setae  were  developed  were  in  similiar  positions  on 
their  respective  segments.  On  the  other  hand  it  is  equally  true  that,  when 
two  setae  of  a  specialized  form  are  in  similar  positions  on  their  respective 
segments,  a  demonstration  that  they  diverge  farther  and  farther  as  we 
study  the  more  and  more  generalized  types  shows  that  they  are  not  true 
homologues  but  have  converged  in  phylogenetic  development.  This  gives 
to  ancestry  the  primary  importance  and  makes  necessary  a  consideration 
of  the  nature  of  the  evidence  which  bears  on  phylogeny. 

DIFFICULTIES 

The  meagerness  of  the  results  thus  far  obtained  on  this  problem  is 
due  partially  to  peculiar  difficulties  in  its  solution.  Certain  obstacles 
stand  in  the  way  of  an  accurate  and  complete  demonstration  of  the 
homology  of  the  setae.  They  are  mentioned,  not  to  emphasize  the  magni- 
tude of  the  task,  but  to  explain  the  fact  that  so  many  doubtful  points 
remain  unsettled. 

The  first  of  these  difficulties  is  caused  by  the  absence  of  intermediate 


16  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [16 

§tages  between  radically  different  conditions.  When  the  tubercles*  have 
been  modified  to  form  scoli  or  verrucae,  it  often  seems  impossible  to 
determine  whether  differences  have  arisen  by  coalescence  or  by  the  dis- 
appearance of  some  of  the  tubercles.  In  many  cases  this  is  a  very  real 
problem,  on  whose  solution  depends  the  correctness  of  the  conception  of 
large  groups. 

Another  obstacle  is  the  lack  of  developmental  series.  In  the  case  of 
wings,  the  tracheae  which  precede  the  veins  in  larval  and  pupal  stages 
plainly  show  the  relation  of  the  adult  venation  to  the  generalized  type. 
The  single  elementary  instar  which  acts  as  a  guide  in  the  study  of  the 
chaetotaxy  of  caterpillars,  however,  is  sometimes  so  unlike  the  mature 
larva  in  the  arrangement  of  its  setae,  that  it  is  of  little  assistance  in  inter- 
preting their  homology.  The  change  is  usually  sudden  and  occurs  at 
molting.  Were  the  recapitulation  more  often  extended  over  several  molts 
the  problem  would  be  easier. 

The  third  difficulty  is  one  that,  up  to  this  time,  has  prevented  prog- 
ress in  this  field.  Apparently  a  lepidopterous  larva  has  three  or  more 
entirely  distinct  types  of  arrangement  of  the  setae  (Figs.  7,  8).  In  only 
a  few  species  is  there  any  apparent  relation  between  the  plan  of  the  pro- 
thorax  and  that  of  the  mesothorax,  or  between  the  last  abdominal  segment 
and  any  of  the  others.  While  this  obstacle  is  not  a  serious  one  in  classifi- 
cation, it  has  prevented  thus  far  the  determination  of  a  satisfactory  no- 
menclature and  therefore  of  a  working  basis.  Since  Wilhelm  Miiller  said 
in  1886  that  he  found  "no  support  for  a  comparison  of  the  prothoracic 
setae  with  those  of  the  following  segments ' ',  workers  seem  to  have  left  the 
prothorax  severely  alone.  They  seem  not  to  have  realized  that  there  is 
evidence  not  found  in  the  Nymphalidae  on  which  Miiller  was  working. 

Fortunately  there  are  partial  hints  and  clews  to  assist  in  surmount- 
ing each  of  these  obstacles.  Study  of  varied  forms  often  yields  signs  of 
intermediate  stages  in  position.  Sometimes  the  single  first  stage,  our 
only  evidence  of  the  past,  unmistakably  points  the  way  to  an  interpre- 
tation we  would  not  otherwise  think  of  making.  Again,  the  presence  of 
a  single  unusual  seta  on  a  single  segment  of  a  generalized  form  will 
unite  the  setal  plans  of  otherwise  seriously  differing  segments.  In  these 
ways  the  gaps  are  at  least  partially  closed  and  the  problem  is  taken  out 
of  the  realm  of  guesswork  and  abstraction. 


*The  word,  "tubercle",  is  used  in  this  paper  as  a  general  term  to  indicate  the 
location  of  a  seta,  or  of  a  definite  group  of  setae,  or  a  process  of  the  body  wall 
bearing  such  a  group. 


17]  LEPIDOPTEROUS    LARVAE  — FRACKER  17 

COMPABATIVE  ANATOMY 

Caterpillars  may  be  said  to  bear  setae  in  all  possible  positions.  Their 
great,  number  and  uniform  distribution  in  some  species  makes  naming 
and  homologizing  them  seem  impossible.  A  little  study  of  the  less 
** hairy"  ones,  however,  soon  shows  that  the  arrangement  is  quite  con- 
stant and  further  investigation  proves  that  they  have  all  been  derived 
from  the  same  typical  plan. 

The  method  used  in  determining  this  plan  was  the  ordinary  one 
in  problems  of  this  kind.  The  setae  of  the  prothorax,  metathorax,  and 
abdomen  of  the  generalized  members  of  both  suborders  of  Lepidoptera 
were  plotted,  one  segment  over  the  other,  as  if  all  were  on  the  same 
segment.  It  was  then  found  that  the  number  of  setae  in  this  composite 
picture  (Fig.  1)  was  about  fifteen,  and  that  they  were  in  approxi- 
mately the  same  position  as  on  the  prothorax  of  the  most  generalized 
forms  of  the  order. 

The  next  problem  concerns  the  relation  of  the  different  segments 
of  a  larva  to  each  other  and  to  the  generalized  type.  It  is  clear  from 
the  first  that  the  prothorax  is  least  modified  throughout  the  series.  We 
can  not  assume,  however,  that  the  setae  of  the  following  segments  of  a 
caterpillar  may  be  directly  homologized  with  the  type  by  comparing 
them  with  the  prothorax  of  the  same  individual.  Differentiation  into 
the  three  types  of  arrangement  must  have  occurred  long  before  the 
suborders  of  Lepidoptera  were  differentiated  from  each  other.  The 
first  insect  with  scaly  wings  and  long  maxillae  probably  arose  from  a 
larva  possessing  a  different  arrangement  of  the  setae  on  the  abdomen 
from  that  on  the  prothorax.  It  is  possible  that  all  of  the  thoracic 
segments  were  similar,  but  the  abdomen  was  certainly  distinct.  In  view 
of  that  fact,  one  easily  sees  that  complete  reliance  on  any  single 
modern  form  is  likely  to  lead  to  error.  An  abdominal  ' '  type ' '  must  be 
worked  out  in  the  way  used  to  establish  a  hypothetical  generalized 
type.  Then  a  comparison  of  the  thoracic  and  abdominal  types  with  the 
general  type  will  bring  us  as  near  as  comparative  anatomy  can,  to  a 
correct  view  of  the  homology  between  the  prothorax  and  abdomen. 

ONTOGENY 

That  the  embryological  development  of  an  animal  has  an  important 
bearing  on  the  study  of  its  phylogeny  has  been  recognized  ever  since 
the  "recapitulation  theory"  was  first  advanced.  This  theory  has  not, 
however,  shown  the  way  to  a  complete  solution  of  the  problems  of 
ancestry.  The  development  of  members  of  nearly  all  animal  groups 
and  that  of  the  rarest  and  most  peculiar  forms  has  attracted  numerous 


18  ILLINOIS  BIOLOGICAL  MONOGRAPHS  (18 

workers.  Many  problems  still  remain  unsolved, — for  the  recapitulation 
is  neither  direct  nor  easy  to  interpret  and  is  often  covered  by  such  a 
multitude  of  complications,  reversals,  and  omissions  that  we  are  baffled 
in  an  attempt  at  their  solution.  For  this  reason,  before  an  argnment 
can  be  based  on  ontogeny,  it  must  be  shown  that  the  condition  discussed 
is  necessarily  a  recapitulation. 

When  the  larva  of  a  moth  hatches  from  the  egg  it  is  somewhat 
different,  in  most  cases,  from  the  mature  caterpillar.  The  ' '  woolly  bear ' ' 
is  as  naked  as  a  cutworm  and  the  butterfly  larva  could  be  mistaken  for 
a  tortricid.  Sometimes  indications  of  this  peculiar  condition  remain 
after  the  first  molt,  but  usually  this  glimpse  of  the  past  is  as  evanescent 
as  it  is  surprising.  Let  this  minute  "worm"  reach  the  second  instar 
and  nothing  remains  to  show  that  the  arctian  was  not  always  "hairy", 
or  that  the  ancestors  of  the  saturnian  did  not  possess  prominent  seoli. 

The  natural  supposition  that  this  first  stage  is  a  recapitulation  of 
the  past  has  seldom  been  doubted.  Several  arguments,  or,  rather,  sug- 
gestions, may  however  be  advanced  against  it,  and  these  must  be  dis- 
proven  before  this  stage  is  admitted  as  evidence. 

In  the  first  place  it  may  be  urged  that  this  stage  represents  an 
adaptive  condition.  While  it  is  true  that  the  thick  setae  of  an  arctian  or 
the  spiny  processes  of  a  nymphalid  might  prove  an  obstacle  to  hatching, 
this  would  merely  show  that  the  former  condition  had  been  retained 
in  the  first  instar  after  the  appearance  of  the  new  armature  in  later 
development,  rather  than  that  a  new  elementary  stage  had  been  acquired. 
At  the  same  time  such  an  interpretation  can  not  give  us  a  clue  to  the 
reason  for  the  lack  of  one  of  the  setae  (mu)  (cf.  Figs.  29  and  31)  on  the 
abdomen  of  all  the  Frenatae  in  the  first  stage,  and  its  presence  after  the 
first  molt.  Nor  is  it  clear  how  the  absence  of  theta  from  slightly 
different  positions  on  all  the  segments  of  Hepialus  (cf.  Figs.  2,  3,  4 
with  Fig.  6)  could  assist  in  emerging  from  the  egg.  Secondary  adap- 
tation might  explain  a  transformation  in  the  entire  style  of  armature 
but  only  recapitulation  can  suggest  a  reason  for  changes  in  the  presence 
and  position  of  a  single  seta. 

Again,  the  differences  between  the  elementary  stages  of  different 
forms  may  be  pointed  out  and  the  conclusion  reached  that  they  can 
not  therefore  represent  an  ancestral  condition.  While  the  first  stages 
are  not,  it  is  true,  identical  throughout  the  order,  they  do  not  vary 
one-tenth  as  much  as  the  mature  larvae.  These  first  instars  diverge 
slightly  in  several  directions  from  the  ancestral  type,  while  the  mature 
larvae  diverge  rapidly  and  extensively  from  the  type.  The  former  are 
so  nearly  uniform  that  their  evidence  in  regard  to  the  past  is  invaluable. 


19]  LEPIDOPTEROUS    LARVAE  — FRACKER  19 

A  third  position  might  be  taken  with  regard  to  development  by- 
successive  molts  on  the  supposition  that  it  might  not  constitute  an 
ontogeny  in  the  usual  meaning  of  the  term.  At  the  same  time  it  must 
be  recognized  that  the  instars  through  which  a  caterpillar  passes  are 
as  necessary  a  part  of  its  development  as  are  the  changes  within  the  egg. 
Specific  evidence  of  recapitulation  in  the  life  history  of  animals  which 
molt  is  taken  up  in  a  later  paragraph. 

Constructive  evidence  on  the  recapitulation  theory  as  applied  to 
larval  instars  is  considerable  in  amount.  Some  of  it  has  been  sug- 
gested in  answering  the  objections  and  merely  the  outline  of  this  evidence 
is  given  below.    There  is  no  need  to  develop  the  different  points. 

I.  The  instars  of  other  Arthropoda  recapitulate  their  ancestral 
history.  Examples:  Sacculina  and  its  degeneration;  the  changes  of 
barnacles ;  the  zooea,  mysis  stages,  etc.,  of  Decapoda. 

II.  The  phylogeny  of  other  insects  is  shown  by  their  postembryonie 
development.  Examples:  in  Coccidae,  the  presence  of  the  anal  ring  in 
the  nymphs  of  Kermesinae,  and  the  appearance  of  primary  and  secon- 
dary pygidia  in  certain  Diaspinae ;  in  Coleoptera,  the  campodeiform 
larva  preceding  the  cruciform  in  certain  cases. 

III.  The  development  of  the  setal  plan  of  lepidopterous  larvae 
itself  bears  prima  facie  evidence  that  it  constitutes  a  recapitulation. 
1.  All  the  Frenatae  are  almost  identical  in  the  first  instar  when  that 
stage  is  different  from  later  ones.  2,  The  first  stage  of  the  Jugatae  is 
much  nearer  that  of  the  Frenatae  than  later  stages  are.  3.  Larvae  with 
tufted  setae,  as  arctians,  usually  possess  only  the  primary  setae  before 
the  first  molt  and  these  are  in  the  typical  position.  4.  The  armature 
of  the  larvae  of  Nymphalidae  and  certain  other  butterflies  or  specialized 
Lepidoptera  is  not  homologous  with  that  of  the  moths  but  is  preceded 
in  the  first  stage  by  the  setae  in  the  typical  position.  5.  The  absence 
of  theta  on  all  the  segments  of  Hepialus  and  the  Frenatae  in  the  first 
stage,  and  its  presence  on  all  the  segments  of  Hepialus  and  on  the  thorax 
of  Frenatae  in  the  next  stage,  can  have  no  other  meaning  than  that  this 
seta  is  a  later  arrival  than  those  which  are  present  from  the  time  of 
hatching  and  that  it  has  become  established  in  the  Frenatae  on  the  thorax 
only.  6.  Setae  are  distinct  in  the  first  instar  of  Sphingidae,  Dioptidae^ 
and  other  groups,  but  are  very  much  reduced  or  wanting  later.  At  the 
same  time  their  descent  from  forms  in  which  the  setae  are  distinct  is 
unquestionable. 

The  writer  has  become  convinced  from  many  facts  of  which  the 
preceding  are  only  examples,  that  the  first-stage  larva  of  Lepidoptera 
represents  the  ancestral  type;  that  the  arrangement  of  the  setae  in  this 
instar  is   essentially   the   same   their   ancestors   bore   in   some    remote 


20  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [20 

antiquity.  While  it  does  not  extend  back  to  that  distant  age  when  all 
the  segments  bore  the  same  setal  plan,  it  furnishes  a  connecting  link 
between  that  period  and  the  present  day.  I  have  no  hesitancy  in  denomi- 
nating, as  Dyar  does,  a  seta  as  only  "subprimary"  when  it  is  con- 
stantly wanting  in  the  first  stage,  however  invariable  may  be  its  presence 
in  the  second.  For  the  same  reason  I  can  not  consider  a  subprimary 
seta  of  a  specialized  group  as  homologous  with  a  primary  one  of  a 
generalized  group.  Such  an  homology  is  entirely  inconsistent  with  the 
recapitulation  theory. 

In  a  word,  the  arrangement  of  the  setae  in  the  larvae  of  the  Lepi- 
doptera  gives  us  every  reason  to  believe  and  no  cause  to  deny  the  hypo- 
thesis Weismann  expressed  in  1876:  "New  characters  first  appear  in 
the  last  stage  of  individual  development;  these  move  back  gradually 
into  the  earlier  stages  and  so  crowd  out  the  older  characters  until  the 
latter  finally  disappear." 

VARIATION 

In  many  cases  the  presence  of  secondary  or  tufted  setae  is  con- 
fusing in  determining  the  location  of  the  primary  ones.  The  acquisition 
of  additional  scattered  setae  in  one  species  or  genus  is  a  very  common 
occurrence  and  caution  should  be  used  in  giving  this  character  as  bound- 
ing any  group.  The  condition  in  Drepanidae,  Thyatiridae,  and  Geomet- 
ridae  furnishes  good  examples. 

When  several  primary  setae  are  united  by  being  surrounded  by  a 
chitinized  plate  they  have  a  tendency  to  vary  in  number.  This  is  true 
of  the  Pi  group  on  the  proleg-bearing  segments  of  the  abdomen.  Pi 
itself  consisted  originally  of  two  primary  setae  but  tau  is  usually  asso- 
ciated with  them.  In  many  Noctuidae  the  three  are  borne  on  a  chitinized 
leg  plate.  In  notodontians,  arctians,  and  other  groups  specialized  from 
the  ancestral  noctuid  type,  this  plate  bears  many  setae,  none  of  which 
can  be  homologized  with  the  primary  ones  (cf.  Figs.  31  and  33). 

III.    Application  op  the  Evidence 

As  stated  above,  two  setae  on  different  segments  of  the  same  or 
different  larvae  are  homologous,  regardless  of  their  position  at  the 
present  time,  when  they  have  descended  from  the  same  or  homologous 
organs  of  a  generalized  ancestor.  It  follows  from  the  definition  that  no 
single  case  of  homology  can  be  absolutely  proven.  No  combination  of 
circumstances  is  sufficient  to  show,  beyond  the  shadow  of  a  doubt,  that 
two  setae  on  a  modern  larva  are  descendants  from  the  same  or  homol- 
ogous structures  of  some  extinct  ancestor.  Nature's  directions  are, 
however,  sufficiently  clear  to  remove  the  problems  completely  from  the 


21]  LEPIDOPTEROUS    LARVAE— FR ACKER  21 

realm  of  speculation.  Let  us  consider  for  a  moment  the  nature  and  kind 
of  these  indications  and  their  use  as  evidence  on  a  correct  nomenclature 
of  the  setae. 

APPLICATION    OP   PRINCIPLES 

Similar  position  in  all  modern  forms. — When  a  group  of  setae  are 
in  similar  positions  throughout  the  entire  series  of  mature  caterpillars, 
we  may  conclude  that  they  are  homologous  with  each  other.  If  further 
evidence  does  not  point  distinctly  in  some  other  direction,  we  can  not  go 
back  of  this  stand.  Practically  every  segment  of  every  caterpillar  bears 
one  seta  near  the  medioventral  line  on  each  side.  This  the  writer  calls 
sigma  and  it  is  clear  that  in  these  setae  we  are  dealing  with  truly  homo- 
logous organs ;  that  on  the  thoracic  and  abdominal  segments  in  Hepialus 
as  well  as  the  Frenatae,  these  ventral  setae  are  homotypes. 

Similar  position  on  certain  segments  of  all  modern  forms.  A  nearly 
uniform  arrangement  of  the  setae  on  the  prothorax  of  practically  all  the 
members  of  the  order  is  excellent  evidence  that  this  arrangement  is 
ancestral  and  that  it  has  not  arisen  through  convergent  development. 
On  the  other  hand,  such  a  condition  cannot  bear  on  the  relations  of  the 
segments  to  one  another. 

Similar  arrangement  on  all  the  segments  in  the  most  generalized 
groups.  Every  structure  of  Hepialus  points  to  the  view  that  this  genus 
is  one  of  the  most  generalized  of  Lepidoptera.  While  distinctly  in  a  dif- 
ferent suborder,  it  bears  much  evidence  that  it  is  closer  to  the  ancestral 
type  than  are  most  of  the  Frenatae,  When  we  find  in  it,  therefore,  that 
the  relations  (Figs.  5,  6, 13, 14)  of  alpha,  beta,  and  rho,  to  each  other  and 
to  the  boundaries  of  the  segments,  are  identical  throughout  the  body, 
we  have  reason  to  believe  that  they  are  homologous  in  spite  of  their 
changed  position  in  the  Frenatae  on  the  mesothorax  and  metathorax.  It 
simply  remains  to  derive  the  condition  found  on  these  two  segments 
of  Frenatae  from  that  shown  by  the  same  two  segments  of  Hepialus, 
and  again  we  have  a  complete  series  of  homologues. 

Similar  position  on  all  the  segments  of  newly  hatched  larvae. 
The  bearing  of  the  setal  arrangement  of  first-stage  larvae  was  discussed 
under  the  subject  "Ontogeny".  Homologizing  a  seta  never  present  in 
this  stage  with  another  that  is  present  cannot  usually  be  admitted  as 
justifiable.  On  the  abdomen  of  Hepialus  (Figs.  6,  13)  there  are  three 
setae,  theta,  kappa,  and  eta,  in  a  long  diagonal  row  caudad  and  ventrad  of 
the  spiracle.  Of  these,  the  upper  one  is  absent  from  the  first  stage  on  all 
the  segments  and  therefore,  according  to  Weismann's  hypothesis,  may 
be  assumed  to  be  of  more  recent  origin.  It  would  certainly  be  incorrect 
to  homologize  it  with  any  primary  seta  of  generalized  Frenatae. 


22  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [22 

Series  of  changes.  Ordinarily  two  setae  in  the  same  relative  position 
on  their  respective  segments  are  considered  homologous.  Two  setae  in 
different  positions  may  be  homologous,  however,  if  they  have  reached 
these  new  positions  by  migrations  during  phylogeny.  In  many  cases 
an  intermediate  location  is  shown  by  the  first  instar,  while  in  others  a 
large  number  of  mature  larvae  will  show  a  complete  series  of  steps  in 
the  migration  from  the  old  position  to  the  new  one. 

CHOICE  OF  A  NOMENCLATURE 

At  the  present  time  Roman  numerals  are  in  more  or  less  general  use 
as  a  means  of  denominating  the  setae  of  lepidopterous  larvae.  They 
were  introduced  by  Dyar  and  have  been  retained,  largely  in  their  original 
sense,  partly  because  the  great  majority  of  recent  papers  describing 
caterpillars  have  been  written  by  this  worker.  The  wide  distribution 
of  his  papers  and  the  undoubted  accuracy  of  his  observation  would  lead 
the  present  writer  to  adopt  his  nomenclature  if  that  were  possible.  For 
several  reasons,  however,  it  seems  that  the  use  of  numbers  in  this  con- 
nection is  no  longer  desirable. 

In  the  first  place  the  abdomen  of  Frenatae,  upon  which  the  numeral 
system  was  based,  can  not  represent  the  original  type.  In  some  particu- 
lars it  differs  radically  from  the  same  segments  of  the  Jugatae.  Attempts 
to  derive  the  setal  plan  of  the  thoracic  segments  from  this  arrangement 
and  to  find  any  evidence  for  such  a  derivation  have  been  fruitless.  The 
original  type  segment,  or  better,  the  potential  arrangement  from  which 
the  modern  plan  has  been  derived,  must  have  included  a  greater  instead 
of  a  smaller  number  of  setae  than  are  at  present  found  on  the  meso-  and 
metathorax.  Many  of  the  thoracic  setae  are  undoubtedly  as  primary 
and  as  ancestral  as  those  on  the  abdomen,  and  the  same  is  true  of  some 
of  the  additional  setae  shown  on  Hepialus;  therefore,  if  Dyar's  numerals 
are  used  we  should  be  compelled  either  to  give  letters  and  subnumerals 
to  primary  setae  simply  because  they  are  not  present  on  the  abdomen 
of  modern  caterpillars,  or  to  adopt  his  scheme  for  the  abdomen  of  Fren- 
atae and  apply  a  different  one  to  all  other  body-segments  and  to  the 
Jugatae.  Neither  of  these  methods  would  fulfill  our  hope  of  a  uniform 
nomenclature  based  on  homology  and  applicable  to  all  the  segments  of 
all  lepidopterous  larvae. 

In  the  second  place  any  series  of  names  which  have  as  definite  an 
order  as  numbers  is  sure  to  be  misleading  and  is  likely  to  prejudice  one's 
views  in  regard  to  homology.  The  mere  use  of  numerals  beginning  at 
the  mediodorsal  line  tends  to  cause  one  to  give  the  upper  of  two  setae  the 
smaller  numeral  and  to  neglect  the  fact  that  some  setae  are  absent.  In 
wing  venation,  it  is  found  that  when  numbers  are  used,  workers  tend  to 


23]  LEPIDOPTEROUS    LARVAE  — FR ACKER  23 

neglect  studying  out  the  true  homology.  This  danger  is  still  more  appar- 
ent in  work  on  the  setae,  for  whereas  it  is  rare  to  find  a  branch  of  radius, 
for  example,  crossing  media  and  reaching  the  margin  of  the  wing  back 
of  the  latter,  it  is  an  ordinary  occurrence  for  seta  ii  to  be  found  above 
i,  for  seta  v  to  take  almost  any  position  with  respect  to  iv,  and  for  vii 
to  consist  of  one,  two,  three,  or  many  setae,  either  approximate  to  each 
other,  or  decidedly  remote  in  position. 

In  place  of  the  numerals  now  in  use  the  writer  suggests  Greek  letters. 
They  combine  a  quickly  written  character  for  labeling  plates  and  an 
easily  pronounced  word  with  which  all  scientific  men  are  familiar.  A 
special  letter  can  be  introduced  for  a  subprimary  seta  in  a  limited  group 
without  disarranging  the  system.  The  alphabetical  order  is  not  so  fixed 
in  the  mind  as  to  prejudice  one  in  regard  to  homology.  At  the  same 
time  the  confusion  introduced  by  the  papers  of  Quail  and  Forbes  in 
Dyar's  system  is  avoided  and,  as  long  as  the  Greek  letters  are  retained 
in  the  original  sense,  the  meaning  will  be  absolutely  clear. 

As  it  is  convenient  to  have  a  single  term  for  groups  of  setae  and  for 
compound  tubercles,  such  as  scoli,  the  writer  capitalizes  the  letter  indi- 
cating one  of  the  more  constant  of  the  primary  setae  composing  the 
group.  For  example  a  verruca  bearing  a  tuft  of  setae  developed  from 
the  group  consisting  of  theta,  kappa,  and  eta,  is  known  as  the  verruca 
of  the  Kappa  group  and  labeled  ^'K"  (cf.  Figs.  7  and  25).  In  cases 
where  there  is  doubt  about  the  number  of  primary  setae  from  which  a 
scolus  or  verruca  is  developed,  the  capital  letter  is  usually  employed. 
This  method  is  particularly  valuable  where  it  is  impossible  or  disad- 
vantageous to  indicate  the  components  of  the  group.  The  names  of  the 
groups  and  the  setae  composing  them  are  given  on  page  39. 

As  mentioned  on  a  previous  page,  a  seta  is  known  as  primary  when 
it  is  present  on  the  newly  hatched  larva.  If  it  first  appears  after  one 
of  the  molts  but  is  fairly  constant,  it  is  known  as  subprimary,  e.g.,  mu, 
theta,  etc.  Secondary  setae  are  those  which  have  no  constant  position, 
are  more  or  less  numerous  and  scattered,  are  not  ancestral,  and  bear 
absolutely  no  relation  to  the  primary  setae.  They  are  very  rarely  found 
in  the  first  instar.  The  individual  setae  of  a  tuft  borne  on  a  verruca 
are  not  given  distinctive  names,  the  group  itself  being  called  primary  or 
subprimary  according  to  its  origin.  The  numerous  setae  which  it  bears 
are  not  considered  secondaries. 

IV.    Setal  Arrangement  in  the  Principal  Superpamilies 

In  this  section  the  larval  chaetotaxy  of  a  number  of  typical  species 
is  described.  Each  seta  is  named  when  it  is  first  mentioned  in  the 
description,  the  same  name  being  applied  to  its  homotypes  on  other  seg- 


24  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [24 

ments  and  other  larvae  as  they  are  reached.  While  it  is  not  feasible  to 
discuss  their  homology  in  detail  in  this  place,  some  of  the  evidence  sup- 
porting the  view  expressed  is  usually  given,  except  where  the  corre- 
spondence is  entirely  obvious.  Section  V  then  takes  up  each  seta  in  turn, 
follows  it  through  its  principal  migrations  and  modifications,  and 
briefly  summarizes  the  evidence  for  each  case  of  homotypy. 

SUBORDER  JUGATAE 

Of  the  suborder  Jugatae  the  writer  has  studied  in  detail  but  one 
genus,  Hepialus,  and  the  description  will  be  limited  to  it.  The  setae  of 
larval  Micropterygidae  have  been  so  reduced  by  leaf -mining  habits  that 
conclusions  can  not  be  based  on  them.  Hepialus,  on  the  other  hand, 
seems  still  to  be  generalized  and,  as  its  wings  gave  Comstock  the  clew 
to  the  ancestral  venation,  so  its  chaetotaxy  has  suggested  the  generalized 
setal  plan. 

Had  Dyar  studied  the  prothorax  of  the  larvae  of  this  genus  as  care- 
fully as  he  did  the  other  segments  the  following  description  would  not  be 
necessary.  As  it  is,  the  writer  is  compelled  to  rely  on  his  figure  of  the 
first  stage ;  for  up  to  the  present  time  no  newly  hatched  larvae  have 
been  available  for  study.  As  this  first  stage  is  essential  in  the  determi- 
nation of  homology,  my  results  are  based  on  the  assumption  that  his 
figures  are  corrept.  Descriptions  of  the  later  stages  in  this  paper  were 
made  from  Hepialus  humuli,  verified  by  comparison  with  H.  hectus  and 
H.  lupulinus,  two  or  more  individuals  of  each  species  being  studied. 

First  Instar 
[Figs.  2,  3,  4] 

The  prothorax  of  the  newly  hatched  larva  (Fig.  2)  bears  six  setae 
above  the  spiracle,  two  in  front  of  it,  two  between  it  and  the  leg,  and  one 
in  front  of  the  leg.  No  ventral  setae  are  indicated.  Those  above  the 
spiracle  are  in  two  transverse  rows  of  three  setae  each,  those  in  the  caudal 
row  being  much  closer  together  and  farther  ventrad  than  those  of  the 
cephalic  row.  As  shown  on  the  figures,  I  have  named  those  on  the  ceph- 
alic row,  alpha,  gamma,  and  epsilon,  and  the  caudal  group,  beta,  delta, 
and  rho,  beginning  in  each  case  near  the  dorsomeson.  In  front  of  the 
spiracle,  kappa  and  eta  represent  the  Kappa  group,  and  between  the 
spiracle  and  the  leg  the  two  setae,  pi  and  nu,  form  the  Pi  group.  The 
seta  in  front  of  the  leg  is  tau. 

The  mesothorax  and  metathorax  (Fig.  3)  are  practically  identical 
in  their  arrangement.  As  there  is  no  spiracle,  let  us  describe  the  setae 
as  above  and  below  kappa,  the  single  seta  at  the  level  of  the  prothoracic 


25]  LEPIDOPTEROUS    LARVAE  — FRACKER  25 

spiracle.  Above  it  are  only  five  setae,  two  in  a  cephalic  and  three  in 
a  caudal  row.  The  homology  is  perfectly  evident,  gamma,  the  middle 
of  the  three  setae  of  the  prothorax,  being  the  only  absentee,  and 
alpha,  beta,  delta,  rho,  and  epsilon  having  the  same  position  as  before. 
Below  kappa  is  located  pi,  the  caudal  seta  of  the  Pi  group.  Tau  occupies 
the  same  position  as  before. 

We  thus  find  that  all  the  thoracic  segments  in  this  instar  are  arrang- 
ed on  the  same  plan  but  that  the  prothorax  bears  three  more  setae,  gam- 
ma, eta,  and  nu,  than  the  other  two  segments.  Whether  these  setae  have 
been  lost  from  the  second  and  third  segments  or  added  to  the  first  will 
be  discussed  in  a  succeeding  paragraph. 

On  the  abdomen  (Fig.  4)  above  the  spiracle  there  are  only  four 
setae,  two  in  each  transverse  row.  The  cephalic  row,  exactly  as  in  the 
metathorax,  consists  of  alpha  and  epsilon,  but  in  the  caudal  row  delta 
is  wanting.  Four  of  the  six  dorsal  prothoracic  setae  are  then  retained 
on  the  abdomen.  Of  the  lateral  setae,  kappa  and  eta  are  both  present  as 
on  the  prothorax  but  they  are  widely  separated.  It  will  be  shown  later 
that  this  separation  is  not  of  great  importance  in  showing  the  ances- 
tral condition  or  the  homotypy,  for  on  the  abdomen  of  the  Microlepid- 
optera,  kappa  and  eta  are  approximate  as  they  are  on  the  prothorax. 
Unquestionably  they  have  been  derived  from  the  same  source  on  all  the 
body  segments. 

At  the  base  of  the  proleg  are  foTind  two  cephalolateral  setae  and 
one  cephalic  seta.  The  first  two  are  almost  directly  behind  pi  on  the 
metathorax  and  clearly  represent  pi  and  nu.  As  the  other  is  in  front  of 
the  proleg  and  bears  the  same  relation  to  it  that  tau  does  to  the  thoracic 
leg,  it  doubtless  represents  that  seta.  We  may  therefore  conclude  that 
the  arrangement  of  the  abdominal  setae  is  homotypic  with  that  of  the 
prothoracic. 

Later  Instars 

[Figs.  5,  6,  13,  14] 

The  mature  larva  of  Hepialus  differs  in  some  important  particulars 
from  the  condition  in  the  first  stage.  Most  of  these  differences  were 
pointed  out  by  Dyar  and  their  bearing  on  phylogeny  was  discussed.  Our 
point  of  view  is  somewhat  different  from  his,  for  we  are  considering  homo- 
typy, a  field  which  he  did  not  enter. 

The  most  striking  change  brought  about  at  the  first  molt  is  the 
appearance  of  a  certain  seta,  theta,  on  each  segment.  This  is  always 
caudad  of  kappa  and  dorsad  of  it  on  all  but  the  prothoracic  segment. 
It  is  the  best  established  subprimary  seta  in  the  whole  order,  for  it  sud- 


26  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [26 

denly  appears  at  the  first  molt  on  all  the  segments  of  Hepialus  and  on  the 
mesothorax  and  metathorax  of  Frenatae.  Another  late  arrival  is  omega, 
situated  between  nu  and  tau  on  the  abdomen.  Whether  it  is  present 
in  the  first  stage  on  the  thorax,  I  do  not  know,  but  in  the  mature  larva 
it  is  on  the  ventral  surface  of  the  thoracic  as  well  as  of  the  abdominal 
segments. 

The  mature  larva  of  Hepialus  humuli  may  then  be  described  as 
follows : 

Prothorax  (Fig.  5) .  Six  setae  are  located  above  the  spiracle  and  three 
in  front  of  it.  All  of  these  are  placed  on  the  cervical  shield,  which  ex- 
tends ventrad  to  the  level  of  the  middle  of  the  spiracle.  Along  the  ceph- 
alic border  of  the  shield  are  five  setae  the  upper  three  of  which  are  alpha, 
gamma,  and  epsilon,  as  described  on  the  first-stage  larva.  The  lower  two, 
kappa  and  eta,  in  front  of  the  dorsal  margin  of  the  spiracle,  are  lateral 
in  position  and  belong  to  the  Kappa  group.  On  the  caudal  margin  of  the 
shield  is  a  group  of  three  setae,  beta,  delta,  and  rho,  arranged  in  a  curved 
line  directly  above  the  spiracle.  Slightly  separated  from  these  is  another, 
ventrad  of  the  lower  end  of  this  line.  The  latter  is  theta,  the  third 
member  of  the  Kappa  group,  and  is  always  associated  with  kappa 
and   eta. 

Near  the  coxa  of  the  leg  is  a  chitinized  plate  bearing  two  setae,  pi 
and  nu,  representing  the  constant  and  important  Pi  group.  In  front 
of  the  leg  are  certain  small  setae,  usually  two  in  number,  with  a  third 
sometimes  added.  These  I  call  the  Tau  group,  for  they  are  extremely 
variable  and  it  is  difficult  to  homologize  the  individual  setae.  They  are, 
however,  not  related  to  each  other  in  the  same  sense  as  the  members  of 
the  Kappa  group,  Pi  group,  etc.  The  one  closest  to  Pi  may  be  called 
omega,  and  the  others,  tau  and  phi.  Behind  the  coxa,  as  in  all  cater- 
pillars, sigma  is  present  near  the  ventromeson. 

Mesothorax  and  Metathorax  (Fig.  5).  These  segments  are  each 
divided  into  three  annulets,  marked  distinctly  on  the  dorsal  half  of  the 
segment  but  partially  lost  on  the  ventral.  On  the  first  of  these  is  found 
a  group  of  three  minute  setae,  which  must  represent  gamma  or  a  struc- 
ture developed  in  its  place.  As  it  is  in  the  position  of  gamma  it  is  most 
convenient  to  give  it  that  name  altho  the  evidence  is  not  conclusive.  The 
middle  annulet  bears  two  setae,  one  near  the  dorsomeson,  the  other 
directly  caudad  of  the  prothoraeic  spiracle.  These,  as  in  the  first  stage, 
are  clearly  homologous  with  alpha  and  epsilon.  Assuming  that  the 
homology  suggested  in  regard  to  the  first  annulet  is  correct,  we  now 
have  the  entire  row,  alpha,  gamma  and  epsilon,  accounted  for. 

The  third  annulet  bears  three  subdorsal  setae  and  two  lateral  ones. 
The  three  subdorsal  are  plainly  beta,  delta,  and  rho,  as  on  the  pro- 


27]  LEPIDOPTEROUS    LARVAE  — FR ACKER  27 

thorax.  They  are  somewhat  more  dorsal  in  position  and  not  so  close 
together,  but  other\vise  clearly  represent  the  same  structures.  The  two 
lateral  setae  are  in  the  same  position  as  the  Kappa  group.  The  caudal  one 
is  clearly  theta,  for  it  was  not  found  on  the  newly  hatched  larva;  but 
the  other  may  be  either  kappa  or  eta.  I  have  labeled  it  kappa,  altho 
there  is  no  evidence  in  this  one  species  that  it  may  not  have  developed 
from  eta  instead.  We  shall  see,  however,  that  eta,  when  present  on 
the  thorax,  as  in  most  of  the  Frenatae,  takes  a  position  quite  distinct 
from  that  shown  here,  while  kappa  is  usually  found  in  this  place.  The 
homology  as  given,  is  therefore  undoubtedly  correct. 

Laterad  of  the  leg  and  close  to  the  coxa  is  a  single  seta,  often  borne 
on  a  chitinized  plate.  This  is  pi,  the  only  representative  of  the  Pi  group 
ever  found  on  the  mesothorax  except  in  a  few  cases.  The  Tau  group  and 
sigma  are  also  present. 

Abdomen.  The  relation  of  the  type  of  arrangement  of  the  setae  of 
the  abdomen  (Fig.  13)  to  that  of  the  thorax  can  not  be  determined  from 
a  study  of  the  mature  larva  alone.  This  is  due  to  the  addition  of  several 
new  setae  at  the  first  molt  and  the  changed  position  of  others.  As  in  the 
first  instar,  there  are  four  setae  above  the  level  of  the  spiracle,  but  these 
do  not  so  clearly  represent  the  two  transverse  rows  as  before.  The 
ventral  seta  of  the  caudal  row,  rho,  had  migrated  cephalad  to  the  middle 
of  the  segment  even  before  the  first  molt  and  is  now  found  very  close 
to  epsilon  and  associated  with  it  above  the  spiracle.  The  fact  that  this 
is  actually  rho  and  that  it  has  come  from  the  caudal  part  of  the  seg- 
ment can  not  be  doubted  after  seeing  figures  of  the  newly  hatched  larva 
and  studying  the  record  of  this  seta  throughout  other  members  of 
the  order. 

In  the  spiracular  region  are  three  setae  in  a  diagonal  line,  theta 
and  kappa  caudad  of  the  spiracle  and  eta  some  distance  ventrad.  Kappa 
and  eta  were  noted  in  the  first  instar  but  theta  was  missing.  The  latter 's 
relative  position  on  the  abdomen  is  the  same  as  that  of  its  homotype  on 
the  thorax. 

Below  eta  the  maximum  number  of  setae  on  any  segment  except 
the  last  is  five.  These  are  arranged  differently  as  we  pass  caudad.  In 
Hepialus  humuli  all  are  present  on  the  first  six  abdominal  segments, 
but  one  of  those  on  the  first  segment  is  much  smaller  than  the  others. 
It  is  entirely  missing  from  this  segment  of  H.  lupulinus  and  H.  hectus. 
On  the  second  segment  the  arrangement  is  more  typical.  Two  setae,  pi 
and  nu,  are  close  together  near  the  middle  of  the  segment  and  only 
slightly  more  ventrad  than  their  homotypes  on  the  thorax.  Sigma  is 
present  as  usual  near  the  ventromeson.     This  leaves  only  two  setae, 


28  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [28 

and  they  are  in  the  same  position  here  as  the  Tau  group  on  the  thorax, 
so  the  entire  homology  is  clear,  as  labeled  on  the  plate. 

On  the  proleg-bearing  segments,  omega  varies  between  a  mesocephalic 
position  at  the  base  of  the  leg  in  some  species  to  a  laterocephalic  location 
in  others.  In  the  latter  position  it  is  quite  closely  associated  with  the 
Pi  group  and  seems  to  belong  to  it  rather  than  to  the  group  from  which 
it  was  derived.  On  segments  7,  8,  and  9,  it  is,  however,  wanting,  so  that 
these  segments  bear  four  sub  ventral  setae,  nu  and  pi  representing  the 
still  bisetose  Pi  group,  tau  alone  remaining  of  the  group  which  bears 
its  name,  and,  as  usual,  sigma  near  the  medioventral  line. 

In  many  caterpillars  the  ninth  abdominal  segment  shows  a  very 
puzzling  condition,  analogous  to  that  on  the  mesothorax.  There  is  a 
tendency  for  the  setae  to  arrange  themselves  in  a  single  transverse  line, 
challenging  the  investigator  to  say  which  is  which.  The  larvae  of  Hepialus 
(Fig.  14),  however,  have  not  undergone  so  much  change,  and  homologiz- 
ing  the  setae  on  this  body-segment  is  not  so  difficult.  As  usual  alpha  and 
beta  are  found  near  the  mediodorsal  line  with  rho  and  theta  below  them. 
Epsilon,  altho  present  on  the  preceding  segments,  is  wanting  here,  but 
it  is  such  an  evanescent  seta  that  its  absence  in  this  place  is  not  sur- 
prising. Kappa  and  eta  are  somewhat  closer  together  and  farther  caudad 
and  dorsad  than  before,  but  the  homology  is  clear.  This  leaves  only  the 
subventral  setae,  which,  as  was  stated  in  the  last  paragraph,  are  identical 
with  those  on  segments  7  and  8. 

The  most  difficult  problem  of  all  still  remains  and  we  can  give  it 
only  a  partial  answer.  Had  we  all  the  ancestors  of  Hepialus  there 
might  still  be  a  doubt  as  to  the  meaning  of  the  anal  segment.  Is  there 
a  tenth  segment  and  then  a  telson  representing  the  eleventh?  Does 
the  proleg  belong  to  the  tenth  or  to  the  eleventh  segment  and  does  it 
bear  the  setae  of  both  segments  or  of  only  one  of  them  ?  What  is  the  ori- 
gin of  the  setae  on  the  caudal  aspect  ?  The  condition  in  Hepialus  larvae 
is  as  follows : 

On  the  dorsal  half  of  the  last  abdominal  segment  (Fig.  14)  is  a 
semicircular  plate  whose  diameter  is  the  cephalic  border  of  the  segment. 
On  each  side  of  the  meson  this  plate  bears  three  setae,  two  in  a  longi- 
tudinal line  comparable  to  the  position  of  alpha  and  beta  on  the  other 
segments,  and  one  farther  laterad  and  cephalad.  Between  the  plate 
and  the  anus  is  a  pair  of  fleshy  projections,  the  suranal  lobes,  each  bear- 
ing one  seta  on  its  caudal  aspect.  Below  the  anus  another  pair  of  lobes 
and  the  prolegs  bear  a  total  of  eight  setae.  Two  of  these  are  on  the  cau- 
dal aspect  of  the  ventral  lobe,  four  on  the  lateral  aspect  and  one  on  the 
caudal  aspect  of  the  proleg,  and  the  other  cephalad  of  the  proleg. 


29J  LEPIDOPTEROUS    LARVAE  — FRACKER  29 

In  the  first  place  it  should  be  noted  that  while  it  is  possible  to  name 
these  structures,  there  is  no  great  amount  of  evidence  as  to  their  true 
homology.  If  we  call  those  on  the  plate  epsilon,  beta,  and  rho,  then  the 
one  on  the  suranal  lobes  must  be  theta.  This  would  indicate  that  the 
tenth  segment  is  very  similar  to  the  ninth  and  gives  us  a  hint  as  to  the 
other  setae.  The  one  on  the  mesocephalic  aspect  of  the  proleg  would 
thus  be  tau,  and  the  one  in  a  mesocaudal  position,  sigma,  while  the  four 
on  the  lateral  aspect  would  represent  pi,  nu,  omega,  and  phi.  Calling  the 
two  setae  behind  the  proleg  kappa  and  eta,  completes  the  series. 

These  setae  have  been  named  not  so  much  to  express  an  opinion 
regarding  their  homology  as  to  show  that  only  one  set  is  present.  There 
is  only  one  more  seta  (phi)  on  this  segment  than  on  any  of  the  other 
proleg-bearing  ones  and  one  (epsilon)  is  missing.  We  may  consequently 
conclude  that  the  setae  give  no  evidence  for  considering  the  anal  segment 
to  be  composed  of  more  than  one  metamere  either  in  its  dorsal  or  ventral 
portions.  The  proof  is  especially  clear  either  that  the  suranal  plate 
does  not  represent  a  telson,  or  that  if  it  does  the  dorsal  half  of  segment 
10  has  been  entirely  suppressed.  Those  who  have  asserted  that  the 
setae  show  that  this  segment  consists  of  more  than  one  somite  have  not 
studied  carefully  the  data  on  which  their  opinions  were  based. 

Conclusions  from  a  Study  of  Jugatae 

Hepialus  has  been  considered  in  detail  because  it  is  very  close  to  the 
typical  form  and  represents  an  entire  suborder,  the  Jugatae.  There  are 
some  primitive  features  about  it  which  give  us  a  clue  to  the  homology 
in  other  groups.  This  is  especially  true  of  the  thoracic  segments,  whose 
relation  to  the  abdomen  and  to  each  other  would  be  whoUy  in  the  dark 
without  this  form.  The  prothorax  shows  the  same  essential  type  of 
arrangement  as  the  other  segments.  It  has  been  a  failure  to  study  He- 
pialus carefully  that  has  caused  Miiller,  Dyar,  Quail,  and  Forbes  to  omit 
the  prothorax  in  their  work  on  the  setae  and  to  consider  its  chaetotaxy 
as  of  wholly  different  origin. 

SUBORDER   FRENATAE 

The  chaetotaxy  of  the  larvae  of  this  suborder  has  been  described 
in  detail  by  Dyar,  and  he  has  also  compared  it  with  the  setal  plan  of 
the  Jugatae.  A  brief  consideration  of  those  modifications  of  the  plan 
which  might  be  confusing  in  a  determination  of  homotypes  is  all  that  is 
necessary  here. 

Bomhycoidea 

The  Noctuidae  are  considered  first,  not  because  they  are  the  most 
generalized  but  because  the  writer  has  studied  no  other  larvae  in  the 


30  ILLINOIS  BIOLOGICAL  MONOGRAPHS  £30 

first  instar.*  The  setal  plan  of  Feltia  gladiaria  in  this  stage  shows  a 
close  correspondence  to  that  of  the  newly  hatched  Hepialus  larva.  On 
the  prothorax  (Fig.  17)  eta  of  the  Kappa  group,  all  the  Tau  group,  and 
sigma  are  wanting.  Otherwise  the  homology  is  clear.  The  mesothorax 
and  metathorax  (Fig.  18)  show  a  condition  which  has  probably  been 
developed  on  account  of  the  great  mobility  of  these  segments.  The  setae 
are  in  a  single  transverse  row.  Above  kappa,  located  caudad  of  the 
prothoracic  spiracle,  are  four  setae  instead  of  the  five  borne  by  Hepialus. 
The  missing  one  proves  to  be  delta,  for  the  close  correspondence  with 
the  abdomen  shows  that  the  dorsal  two  are  alpha  and  beta;  and  the 
others  are  undoubtedy  epsilon  and  rho,  which  are  usually  associated 
together  on  all  segments.  Below  kappa  is  pi,  near  the  proleg.  As  on 
the  prothorax,  the  Tau  group  and  sigma  are  wanting. 

The  abdomen  (Figs.  19,  20,  29)  shows  alpha  and  beta  in  their 
usual  positions  near  the  dorsomeson  except  on  the  first  few  segments, 
where  they  are  more  nearly  in  a  transverse  row,  similar  to  their  arrange- 
ment on  the  metathorax.  Just  dorsad  of  the  spiracle  is  rho,  a  well- 
developed  seta,  and  in  most  cases  a  minute  point  representing  epsilon. 
T^he  latter,  known  as  iii  a  in  the  literature,  is  often  considered  sub- 
primary,  but  the  presence  of  this  rudiment,  which  Bacot  (Quail,  1904) 
says  is  of  common,  if  not  universal,  occurrence  in  all  stages  of  the  larvae 
of  Frenatae,  proves  it  to  be  primary.  Its  small  size  is  the  result  of 
reduction,  rho  having  migrated  caudad  to  the  region  it  once  occupied. 
The  other  abdominal  setae  are  just  as  in  the  first-stage  Hepialus.  In 
Feltia,  tau  is  not  present,  but  in  most  Frenatae  it  is  said  to  be  associated 
with  nu  and  pi  in  all  instars  and  is  usually  considered  a  member  of  the 
Pi  group.  Its  absence  from  the  first,  seventh,  and  eighth  abdominal 
segments  is  a  common  occurrence.  Sigma  is  located  near  the  medioven- 
tral  line  as  usual. 

The  homology  of  the  setae  of  segment  9  (Fig.  30)  may  be  solved  by 
a  comparison  with  the  same  segment  of  the  mature  Hepialus  larva  and 
a  study  of  other  species  which  form  connecting  links  between  the  two 
conditions.  The  evidence  for  considering  the  most  cephalic  of  the  sub- 
dorsal setae  as  alpha,  will  be  given  in  the  next  section.  Beta  is  much 
closer  to  the  dorsomeson,  as  on  the  prothorax.  The  presence  in  some 
species  of  a  minute  seta  (epsilon)  close  to  the  third  seta  shows  the  latter 


*Careful  descriptions  of  first-stage  larvae  of  many  other  groups  have  been 
published,  the  prothorax  usually  being  omitted.  Since  sending  this  paper  to  the 
printer,  the  first  instar  of  Prionoxystus  robiniae  (Cossidae)  has  been  examined 
by  the  writer.  Its  prothorax  is  identical  with  that  shown  in  figures  of  Hepialus 
in  this  stage,  differing  from  noctuid  larvae  in  the  presence  of  two  setae,  instead 
of  only  one,  in  the  Kappa  group. 


31]  LEPIDOPTEROUS    LARVAE  — FRACKER  31 

to  be  rho.  This  leaves  only  three  setae,  which  are  certainly  kappa,  pi, 
and  sigma.  All  of  these  conclusions  are  based  on  series  of  intermediate 
stages. 

Segment  10  bears  only  one  seta  less  than  in  Hepialus  but  the 
homology  is  not  clear. 

The  mature  Feltia  (Figs.  21  to  24,  31,  32)  shows  certain  modifica- 
tions of  the  chaetotaxy  of  the  first  stage.  The  arrival  of  theta  and 
gamma  on  the  mesothorax  and  metathorax,  the  first  caudodorsad  of 
kappa,  the  other  near  the  cephalic  border  of  the  segment,  are  the  only 
changes  duplicated  on  Hepialus.  On  all  the  thoracic  segments  eta  ap- 
pears ventrad  of  kappa.  As  it  was  not  present  at  all  on  the  last  two 
segments  of  Jugatae,  the  condition  here  shows  that  since  its  establish- 
ment on  the  abdomen  it  has  arisen  on  the  thorax,  where,  under  Weis- 
mann  's  law,  it  has  not  yet  reached  the  first  instar.  Finally  mu,  the  most 
recent  arrival  of  all  the  subprimaries,  appears  caudoventrad  of  eta  on 
the  first  eight  abdominal  segments. 

A  significant  change  in  position  also  occurs  after  the  first  molt. 
Epsilon,  located  below  alpha  and  gamma  in  the  cephalic  subdorsal  row 
of  the  prothorax  in  the  first  stage,  now  appears  close  to  rho  above  the 
spiracle.  This  migration  distinguishes  the  Bombycoidea  from  the  Micro- 
lepidoptera,  for  in  the  latter  group  epsilon  remains  near  the  cephalic 
border  of  the  prothoracic  shield. 

Microlepidoptera 

Altho  the  differences  between  the  Noctuidae  and  the  Microlepidop- 
tera are  not  great,  the  latter  are  more  generalized  in  some  important 
particulars.  These  are  best  shown  by  Pseudanaphora  (Figs.  7,  8,  15, 
16),  a  member  of  one  of  the  most  generalized  families  of  the  order.  On 
the  prothorax  theta  is  present,  so  that  all  three  setae  of  the  Kappa  group 
are  accounted  for,  just  as  in  Hepialus.  On  the  abdomen,  kappa  and 
eta  are  at  the  same  level  but  still  distant,  altho  in  all  the  higher  micros 
these  setae  are  close  together  below  the  spiracle.  As  in  the  noctuid 
abdomen,  mu  is  present  and  theta  is  wanting.  Segment  9  shows  nearly 
as  many  setae  as  in  Hepialus,  there  being  only  two  important  differences ; 
the  absence  of  tau  and  theta,  and  the  presence  of  mu  caudoventrad  of 
eta  as  on  the  other  segments. 

Other  Groups 

The  high  specialization  of  the  armature  of  saturnian,  sphingid,  and 
butterfly  larvae  lessens  their  value  as  evidence  on  the  homology  of  the 
setae.  The  first  instar  is  usually  similar  to  that  of  the  Noctuidae.  Only 
one  serious  problem  is  presented,  viz.,  the  origin  of  the  scolus  Kappa 


32  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [22 

in  the  Saturnioidea.  Whether  this  consists  of  kappa  and  eta  or  eta 
alone  is  a  disputed  point,  altho  the  first  instar  seems  to  indicate  the 
correctness  of  the  former  view. 

V.    Primaky  and  Subprimaby  Setae 

In  the  following  discussion  of  the  setae,  the  evidence  for  each  case 
of  homotypy  is  briefly  summari2;ed.  The  plan  followed  is  that  already 
outlined  herein  under  the  title,  "Application  of  the  Evidence."  Other 
authors  have  indicated  various  conceptions  of  homotypy  in  labeling 
their  figures  but  none  have  presented  proof,  except  in  one  case,  the  brief 
paper  by  Quail  mentioned  in  the  introduction.  As  the  evidence  on  all 
the  important  points  is  conclusive,  the  retention  of  an  unnatural  or  un- 
certain nomenclature  is  no  longer  defensible. 

Alpha.  The  position  of  this  seta  as  given  in  the  descriptions  of 
the  groups  is  so  clear  that  a  few  words  here  will  suffice.  Originally 
alpha  seems  to  have  been  farther  dorsad  as  well  as  farther  cephalad 
than  any  other  seta.  This  is  now  true  on  all  the  segments  of  Hepialus, 
on  the  abdomen  of  nearly  all  Frenatae,  and  on  the  prothorax  of  many 
Tineidae  and  Yponomeutidae.  The  prothorax  shows  beta  nearer  the 
meson  than  alpha  in  nearly  all  the  higher  Frenatae,  but  this  is  clearly 
a  later  migration. 

Alpha  is  always  present  in  the  first  stage  and  is  therefore  primary. 
It  is  one  of  the  most  persistent  setae  and  usually  forms  a  verruca  or 
scolus  in  species  bearing  these  structures.  Whether  it  is  present  or  ab- 
sent on  the  last  two  thoracic  segments  of  Frenatae  will  be  discussed 
under  "Beta"  on  a  later  page. 

On  the  ninth  abdominal  segment  of  most  Frenatae,  alpha  is  located 
farther  laterad  than  beta,  and  in  the  Macrolepidoptera,  this  condition 
has  gone  back  into  the  first  instar.  But  in  Hepialus  (Fig.  14),  Scardia 
(Fig.  54),  Thyris  (Fig.  55),  and  other  genera,  it  is  still  as  close  to  the 
dorsomeson  as  on  the  other  abdominal  segments.  In  Pseudanaphora 
(Fig.  16)  the  lateral  migration  has  already  begun  and  in  certain  Py- 
ralididae  (Fig.  49)  it  is  carried  to  its  greatest  extent.  In  many  fami- 
lies the  location  of  this  seta  is  a  character  of  importance  in  the  classifi- 
cation of  genera  (cf.  Pyralididae,  Tortricidae,  etc.,  Part  Two).  The 
close  association  with  rho  in  some  cases  seems  to  cast  doubt  on  the  view 
that  this  seta  is  homologous  with  alpha ;  but  the  position  in  generalized 
larvae,  the  complete  set  of  intermediate  stages  connecting  it  with  its 
other  locations,  the  variation  between  the  original  and  later  positions 
within  limited  groups,  and  the  fact  that  beta,  epsilon,  and  rho  are  oth- 
erwise accounted  for,  show  unquestionably  that  this  seta  must  be  alpha. 

Beta.  On  the  prothorax  as  well  as  the  abdomen  beta  is  always  the 
dorsal  seta  of  the  caudal  row.    Its  position  varies  from  that  in  Hepialus 


33]  LEPIDOPTEROUS    LARVAE  — FRACKER  33 

(Fig.  5),  where  it  is  about  half  way  between  the  spiracle  and  the  dorso- 
meson,  to  that  in  most  Frenatae  (Fig.  21),  where  it  is  closer  to  the 
dorsomeson  than  any  other  seta  of  the  segment.  Intermediate  stages 
are  shown  by  Yponomeutidae  (Fig.  35)  and  Acrolophidae  (Fig.  7). 

The  specializatidn  of  the  mesothorax  and  metathorax  of  Frenatae 
has  been  mentioned.  No  intermediate  stages  exist  to  show  the  relations 
between  the  setal  plan  of  these  segments  of  Hepialus  and  those  of  Frena- 
tae. A  comparison  of  the  thoracic  with  the  abdominal  segments  of  the 
newly  hatched  larva  of  Feltia  (Figs.  18,  19,  20,  29,  30),  however,  indi- 
cates the  direction  the  migration  has  taken.  Segments  6,  7,  and  8  show 
alpha  and  beta  in  their  normal  positions  while  on  segments  1  and  2 
beta  is  almost  directly  ventrad  of  alpha.  The  large  number  of  groups 
in  which  these  two  setae  are  associated  in  the  abdomen,  either  by  being 
borne  on  a  single  pinaculum,  or  uniting  to  form  a  single  verruca,  shows 
that  they  may  easily  become  adjacent.  The  conclusion  is  therefore 
justified  that  the  two  dorsal  setae  of  the  mesothorax  and  metathorax 
are  alpha  and  beta,  in  spite  of  their  changed  position.  Hofmann,  Dyar 
and  Quail  agree  that  this  is  the  true  condition. 

Gamma.  This  seems  to  be  a  comparatively  new  seta  on  all  but  the 
prothorax,  where  it  has  become  established.  The  newly  hatched  larva 
bears  it  only  on  the  one  segment  and  there  its  position  is  constant.  It 
is  often  represented  on  meso-  and  metathoracic  and  abdominal  segments 
as  a  more  or  less  minute  subprimary  seta  near  the  cephalic  border  of 
the  segment  and  in  Hepialus  is  associated  with  two  other  smaller  ones. 
"While  there  is  some  doubt  about  the  accuracy  of  considering  a  primary 
seta  of  the  prothorax  homotypic  with  the  subprimary  one  of  other  seg- 
ments, the  fact  that  the  two  bear  exactly  the  same  relations  to  the  other 
structures  of  the  segment  makes  it  inadvisable  to  use  a  different  name. 
This  will  be  discussed  under  "Eta"  on  a  later  page.  The  probability 
is  that  gamma  is  a  more  recent  seta  than  the  other  primaries  and  be- 
came first  established  on  the  prothorax,  the  order  of  appearance  on  the 
different  segments  now  being  shown  by  ontogeny. 

Delta.  Between  beta  and  rho  on  the  prothorax  of  all  caterpillars 
and  also  on  the  other  thoracic  segments  of  Hepialus  is  delta,  a  seta  never 
found  in  any  other  position  or  on  any  other  segment.  If  ancestral,  it 
has  since  become  lost  on  the  abdomen  of  all  lepidopterous  larvae  and  on 
the  last  two  thoracic  segments  of  all  Frenatae. 

Epsilon.  The  prothoracic  segments  of  Hepialus  and  Pseudana- 
phora  bear  the  third  seta  of  the  cephalic  row  in  its  typical  position.  In 
connection  with  rho  it  goes  through  various  changes  which  are  some- 
times hard  to  follow  on  the  other  body-segments  but  are  evident  on  the 


34  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [34 

prothorax.  In  the  Tortricidae  (Fig.  39),  Aegeriidae,  and  Yponomeu- 
tidae  (Fig.  35),  this  seta  remains  constant  in  position  while  rho  moves 
forward  toward  it.  This  is  distinctly  noticeable  in  Plutella  while  in 
Atteva  aurea  (Fig.  36)  it  has  scarcely  been  begun.  The  opposite  move- 
ment is  to  be  noted  in  all  Macrolepidoptera.  The  newly  hatched  larva 
of  Feltia  shows  rho  and  epsilon  in  their  normal  positions  distant  from 
each  other.  In  the  mature  larva,  however,  epsilon  has  migrated  back  to 
rho,  leaving  only  alpha  and  gamma  remaining  in  the  cephalic  subdorsal 
group. 

On  the  mesothorax  and  metathorax  of  Frenatae,  epsilon  and  rho 
are  again  found  associated.  Like  alpha  and  beta  they  have  yielded  to 
the  mobility  of  this  part  of  the  body  and  been  crowded  to  the  middle 
of  the  segments.  The  first  stage  of  Hepialus  and  Feltia  show  that  epsi- 
lon is  the  upper  of  the  two  and  rho  the  lower.  Both  prothoracic  and 
abdominal  segments  of  Hepialus  and  Cossus  cossus  prove  that  epsilon 
was  originally  above  the  level  of  rho  and  that  its  present  position  ventrad 
of  that  seta  on  the  abdomen  of  many  of  the  species  we  know  today  has 
come  about  through  migration. 

On  the  abdomen  of  Hepialus,  the  presence  and  large  size  of  epsilon 
in  the  first  as  well  as  later  instars  creates  a  serious  problem  if 
that  seta  be  considered  missing  from  its  usual  position  in  the  first  stage 
of  Frenatae.  I  have  been  unable  to  detect  it  in  the  newly  hatched 
Feltia  larva  but  according  to  Quail  (1904),  who  quotes  A.  Bacot,  it  is 
of  general  occurrence  in  all  instars  of  Frenatae.  The  probability  is, 
therefore,  that  it  is  disappearing  from  the  abdomen  and  is  retained  in 
its  former  vigor  only  by  Hepialus  and  Cossus  cossus.  There  seems  to 
be  no  evidence  that  it  is  in  any  sense  subprimary. 

Rho.  The  principal  migrations  of  rho  have  been  described  in  the 
discussion  of  epsilon.  It  is  present  in  all  instars  on  all  segments  of  all 
caterpillars  except  when  obscured  in  later  stages  by  a  secondary  arma- 
ture. Usually  it  is  associated  with  epsilon  when  that  seta  is  present. 
In  species  bearing  verrucae,  epsilon  never  forms  one  distinct  from  that 
of  rho,  except  sometimes  on  the  mesothorax  and  metathorax. 

Theta.  The  dorsocaudal  seta  of  the  Kappa  group  needs  considera- 
tion merely  to  prevent  its  confusion  with  other  setae.  No  question  can 
be  raised  as  to  its  homotypy  on  the  segments  of  Hepialus,  where  it  is 
subprimary  throughout,  in  aU  cases  being  dorsad  and  caudad  of  the 
primary  kappa.  The  same  is  true  on  aU  thoracic  segments  of  the  tineoid 
series  of  Microlepidoptera  and  on  the  meso-  and  metathorax  of  Pyralid- 
idse  and  Macrolepidoptera,  where  it  is  present  and  subprimary. 

Some  confusion  might  arise  concerning  it  on  the  abdomen  of 
Frenatae  in  those  cases  where  kappa  is  well  toward  the  upper  border 


35]  LEPIDOPTEROUS    LARVAE  — FRACKER  35 

of  the  spiracle.  The  fact  that  kappa  is  usually  much  lower  down,  and  is 
often  associated  with  eta,  indicates  the  error  of  a  view  which  would  call 
this  seta  theta.  This  is  further  emphasized  by  the  subprimary  nature  of 
theta  and  by  the  fact  that  eta  and  kappa  already  have  homologues  on 
Hepialus  without  the  use  of  theta.  Forbes'  (1910)  error  on  this  point 
was  rather  far  reaching  so  far  as  homotypy  is  concerned.  He  gives  only 
four  figures,  but  in  the  setae  epsilon,  theta,  kappa,  eta,  and  mu,  there 
are  four  cases*  in  which  the  same  label  is  given  in  one  place  to  a  primary 
and  in  another  to  a  subprimary  seta.  Most  of  these  associations  would 
be  very  difficult  to  explain  and  they  are  wholly  unnecessary.  The  mis- 
takes are  due,  not  to  errors  in  observation,  but  to  a  failure  to  take  the 
primitive  first  stage  into  account. 

Kappa.  This  is  a  fundamental,  ancestral,  primary  seta  and  is  read- 
ily transformed  into  a  scolus  or  verruca.  It  occupies  a  position  about 
the  level  of  the  spiracle  and  is  almost  never  absent.  In  forming  ver- 
rucae  it  is  often  associated  with  theta  and  eta,  and  on  the  prothorax  of 
most  of  the  Microlepidoptera  a  chitinized  pinaculum  bears  all  three.  In 
specialized  Microlepidoptera  kappa  and  eta  are  always  adjacent  on  the 
abdomen,  where  they  take  all  possible  positions  with  respect  to  each 
other.    In  most  cases  the  dorsal  of  the  two  is  called  kappa. 

On  segment  9  kappa  is  obsolete  in  certain  Pyralididae.  The  begin- 
ning of  the  reduction  is  shown  in  Phycitinae  (Fig.  46)  where  eta  is 
located  on  the  same  pinaculum  with  kappa  and  mu  but  is  much  larger 
than  the  other  two.  In  Pyraustinae  (Fig.  49)  only  eta  remains.  This 
condition  is  not  sufficient,  however,  to  justify  us  in  calling  the  sole 
representative  of  the  Kappa  group  on  the  ninth  abdominal  segment  of 
Noctuidae,  "eta",  for  here  the  position  on  the  newly  hatched  larva, 
especially  in  its  relation  to  rho  and  pi,  shows  that  it  is  the  caudal  rather 
than  the  cephalic  seta  of  the  group  which  has  been  retained.  (See  Fig. 
30.) 

Eta.  On  the  meso-  and  metathoracic  segments  of  the  Frenatae,  eta, 
like  theta,  appears  at  the  first  molt.  It  is  below  kappa  and  is  often  asso- 
ciated with  it.  On  Hepialus  it  is  wanting  on  the  mesothorax  and  meta- 
thorax  but  present  on  the  prothorax.  At  the  time  of  the  separation  of  the 
Jugatae  from  the  Frenatae  it  had  appeared  only  on  the  prothorax  and 
abdomen  or  had  been  lost  on  the  other  thoracic  segments.  In  the  latter 
place  it  has  since  become  established  in  the  Frenatae  after  the  first 
instar. 

This  is  one  of  two  cases  where  it  has  seemed  necessary  to  consider 

♦These  are :  iii  (primary  in  all  except  Fig.  4)  ;  iv  (primary  on  Figs.  4,  5,  and 
34,  subprimary  on  Fig.  33)  ;  v  (primary  on  Figs.  5,  33,  and  34,  subprimary  on  Fig. 
4)  ;  vi  (primary  on  Fig.  33,  subprimary  on  Figs.  5  and  34). 


36  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [36 

a  subprimary  seta  on  one  segment  the  homotype  of  a  primary  one  on 
another.  The  fact  that  in  Hepialus  eta  is  present  on  both  the  prothorax 
and  abdomen  but  that  there  is  no  seta  with  which  it  can  possibly  be 
homologous  on  the  mesothorax  and  metathorax,  shows  that  in  the  latter 
place  its  homotype  has  either  been  lost  or  has  never  appeared.  The 
same  conclusion  is  indisputable  after  a  study  of  first-stage  Frenatae. 
Since  the  separation  of  the  two  suborders  a  new  seta  has  appeared  on 
the  caudal  thoracic  segments  in  line  with  eta  of  other  parts  of  the  body. 
This  new  seta  bears  the  same  relation  to  the  other  structures  of  the 
segment  as  eta  does  and  associates  with  kappa  in  the  same  characteristic 
way.  While  its  later  appearance  makes  it  doubtful  whether  the  meso- 
thoracic  seta  should  be  called  a  homotype  of  the  one  on  the  abdomen, 
it  is  clear  that  no  object  would  be  served  by  merely  attaching  to  it  a 
new  name.  We  therefore  depart  to  that  extent  from  a  strict  interpre- 
tation of  our  definition  of  homotypy. 

Pi.  Considerable  confusion  might  exist  at  first  in  regard  to  the 
homology  of  this  and  neighboring  setae.  The  description  of  the  ventral 
half  of  the  larva  of  Hepialus  shows  that  the  homology  there  is  evident 
enough.  Any  other  interpretation  would  involve  one  in  endless  compli- 
cations and  would  necessitate  a  total  neglect  of  the  generalized  first 
larval  stage. 

In  Frenatae,^  however,  the  prolegs  are  much  farther  mesad  than 
the  thoracic  legs  and  the  setae  of  the  two  regions  have  a  less  apparent 
relation  to  each  other.  This  is  complicated  by  the  arrival  of  mu  which 
is  directly  caudad  of  the  thoracic  pi  and  appears  to  be  analogous  with 
it.  Fortunately  the  condition  in  the  newly  hatched  larva  proves  the 
analogy  to  be  more  apparent  than  real,  for  mu  is  not  present  in  the 
ficrst  instar.  This  is  so  constant  a  character  that  Dyar  distinguishes  the 
Jugatae  from  the  Frenatae  by  the  presence  of  this  seta,  "vi",  after  the 
first  molt  in  the  latter  group  while  it  never  appears  in  the  former.  In 
spite  of  this  fact,  Dyar,  Forbes,  and  others  usually  label  pi  on  the 
thorax,  "vi",  indicating  that  it  may  be  homotypic  with  mu  of  the  abdo- 
men. For  that  reason  the  group  requires  more  extended  discussion 
than  the  others  have  received.  In  the  following  summary  of  the  evi- 
dence on  this  point,  "Pi"  is  used  for  the  Pi  group  of  one  or  two  setae 
at  the  base  of  the  thoracic  legs,  "mu"  for  the  subprimar\'  on  the  abdo- 
men, and  "vii"  (following  Dyar)  for  the  lateral  two  of  the  group  of 
three  setae  on  the  prolegs  which  we  are  convinced  are  homotypic  with 
**Pi". 

Pi  must  be  homotypic  with  vii  in  Hepialus  for  mu  is  not  present. 
(Figs.  5  and  6.) 


37]  LEPIDOPTEROUS    LARVAE  — FRACKER  37 

The  first  instar  of  larval  Frenatae  indicates  the  homotypy  of  Pi 
and  vii,  for  no  other  interpretation  is  possible  in  the  absence  of  rau 
(Figs.  17,  18,  19,  29.) 

Pi  and  vii,  in  addition  to  the  fact  that  both  are  primary,  are  both 
"double"  in  all  stages  on  the  prothoracic  and  abdominal  segments  and 
sometimes  on  the  mesothorax  and  metathorax,  while  mu  is  always  single. 

The  multiple  nature  of  Pi  and  vii  is  indicated  by  the  newly  hatched 
larva  of  Panorpa,  of  the  Mecoptera,  described  by  E.  P.  Felt,  1895.  Its 
prothorax  bears  the  same  setal  plan  as  that  of  lepidopterous  larvae  and 
while  the  setae  of  the  other  segments  of  Panorpa  are  reduced  in  number 
the  fundamental  arrangement  is  the  same.  On  every  segment  there  is 
a  pinaculum  bearing  four  to  six  setae  in  a  longitudinal  row  situated  at 
the  base  of  the  leg  or  the  proleg  as  the  case  may  be.  The  fact  that  this 
is  the  first  stage,  all  the  setae  being  lost  later,  and  that  the  Mecoptera 
are  usually  considered  more  generalized  than  the  Lepidoptera,  would 
seem  to  indicate  that  Pi  originated  as  a  multisetiferous  tubercle  and 
that  the  setae  had  been  reduced  to  the  definite  number  two  on  modern 
caterpillars. 

Scolus-bearing  larvae  also  indicate  the  homotypy  of  Pi  on  the  tho- 
rax to  the  group  called  vii  on  the  abdomen.  In  Saturniidae,  e.  g. 
Samia  cecropia  (Fig.  107),  each  thoracic  segment  bears  a  scolus  at  the 
base  of  the  leg,  and  in  line  with  these  scoli  are  found  similar  ones  on 
abdominal  segments  1  and  2.  The  latter  are  not  present,  however,  on 
segments  3  to  6.  As  usual,  vii  of  the  proleg-bearing  segments  is  modified 
into  a  multisetiferous  plate  and  not  into  a  thorn-like  process.  If  the 
scoli  on  segments  1  and  2  represented  the  seta  **vi"  or  mu,  they  would 
also  be  found  on  segments  3  to  6  near  the  base  of  the  prolegs,  as  in 
arctians  and  other  verrucose  larvae,  for  mu  never  takes  part  in  the 
formation  of  a  multisetiferous  leg-plate.  These  scoli  must  then  be  homo- 
types  of  vii.  But  they  are  also  indisputably  homotypic  with  Pi  on  the 
thorax.    Therefore  Pi  and  vii  are  homotypic  and  vii  should  be  called  Pi. 

Dyar  (1901)  interpreted  this  condition  correctly  and  Quail  (1904) 
agreed  with  him.  The  views  expressed  in  this  paper  are  in  accordance 
with  those  of  Quail  on  all  the  setae  which  he  studied.  A  careful  inter- 
pretation of  the  evidence  must  convince  one  that  Pi  is  homologous  with 
"vii"  of  the  abdomen  and  has  no  relation  to  mu. 

Mu.  Mu,  as  has  been  said,  arises  at  the  first  molt  of  Frenatae 
between  eta  and  the  Pi  group.  Apparently  it  is  homotypic  with  pi  of 
the  metathorax,  but  its  absence  from  Hepialus,  Panorpa,  and  the  first 
stage  of  all  caterpillars,  shows  that  this  is  out  of  the  question.  What, 
then,  accounts  for  its  presence? 

The  fact  that  the  prolegs,  and  consequently  the  Pi  group,  on  the 


38  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [38 

abdomen  are  farther  mesad  than  the  thoracic  legs  has  been  noted.  This 
change,  which  is  barely  indicated  in  the  Jugatae,  leaves  a  considerable 
space  between  eta  and  pi  on  the  abdominal  segments.  Assuming  that 
the  setae  are  sensory  in  function,  it  is  clear  that  the  presence  of  a  sense 
organ  in  this  important  area  would  be  of  selective  value.  A  discussion  of 
the  method  of  origin  of  new  or  secondary  setae  in  response  to  a  need 
on  the  part  of  the  organism  would  be  out  of  place  here,  but  that  they 
do  arise  and  are  of  importance  to  the  life  of  the  caterpillar  is  shown 
by  the  conspicuous  differences  between  the  mature  larvae  of  different 
families.  In  this  case  mu  appeared  in  the  center  of  an  area  left  vacant 
by  the  mesal  migration  of  the  prolegs  and  the  Pi  group,  and  has  been 
retained  because  it  is,  like  the  other  sense  organs  of  the  larva,  an 
adaptation  to  the  conditions  of  existence. 

Sigma.  Near  the  medioventral  line  of  almost  every  lepidopterous 
larva,  sigma  may  be  found  in  nearly  the  same  position  on  every  seg- 
ment. So  far  as  known  it  is  never  associated  with  other  setae  except 
in  some  groups  in  which  it  is  drawn  into  the  formation  of  a  multi- 
setiferous  leg-plate. 

Tau.  The  name  Tau  has  been  given  to  an  indefinite  group  of  setae 
between  pi  and  sigma.  Various  numbers  are  present,  ranging  from 
one  to  three  or  four,  or  the  entire  group  may  be  absent.  So  far  as 
known,  only  one  is  ever  present  in  the  first  instar.  This  is  the  cephalic 
or  mesal  seta  of  the  group  of  three  at  the  base  of  the  proleg  on  Frenatae 
and  newly  hatched  Jugatae.  Dyar  calls  all  three  the  "tubercle  vii'* 
but  a  very  little  study  of  the  first  two  abdominal  segments  shows  that 
the  two  caudolateral  members  of  the  group  have  a  distinctly  different 
origin  from  the  other.  When  four  setae  are  found  upon  this  aspect 
of  the  proleg,  as  in  Hepialus,  the  additional  one  is  considered  as 
another  member  of  the  group  Tau.  In  the  description  of  this  genus 
on  a  previous  page  the  individual  setae  of  the  group  were  named,  but 
that  is  scarcely  necessary  in  Frenatae. 

VI.    General  Conclusions. 

The  setal  arrangement  of  every  segment  of  the  body  in  larvae  of  the 
Lepidoptera  has  been  derived  from  the  same  ancestral  type. 

This  type  includes  twelve  primary  setae :  alpha,  beta,  delta,  gamma, 
epsilon,  rho,  kappa,  eta,  nu,  pi,  tau,  and  sigma. 

The  primary  setae  are  present  in  the  first  instar.  They  became 
established  before  the  suborders  of  Lepidoptera  separated  from  each  other 
and  possibly  before  the  separation  of  the  order  from  other  Holometabola. 
It  is  not  necessary  to  assume,  however,  that  there  ever  existed  a  single 


39]  LEPIDOPTEROUS    LARVAE  — FRACKER  39 

insect  larva  having  the  setal  plan  of  all  the  segments  similar  and 
including  only  the  primary  setae  as  given  above. 

The  ancestral  type  has  been  modified  in  three  ways,  each  being 
more  or  less  independent  of  the  other  two.  (a)  The  prothorax  shows 
a  tendency  to  retain  the  maximum  number  of  setae ;  this  is  a  response  to 
the  numerous  sensory  stimuli  which  this  segment  must  transmit,  (h)  The 
mesothorax  and  metathorax  show  a  partial  reduction  and  considerable 
modification  in  response  to  the  necessary  mobility  of  this  portion  of  the 
body,  (c)  The  abdominal  chaetotaxy  has  also  been  reduced  but  the 
setae  tend  to  retain  their  original  typical  position.  Segments  9  and  10 
show  specialized  modifications  of  the  setal  arrangement  of  segments 
1  to  8. 

Subprimary  setae  are  those  which,  altho  they  have  a  definite  location 
on  the  mature  larva  and  are  rather  persistent,  are  absent  from  the 
first  instar. 

New  setae  have  usually  appeared  first  in  that  part  of  the  body  in 
which  they  were  of  most  benefit,  e.  g.,  gamma  on  the  prothorax  and  eta 
on  the  abdomen.  In  some  cases  setae  which  seem  to  be  homologous  with 
them  have  arisen  later  on  other  segments.  The  order  of  their  appearance 
is  now  shown  in  ontogeny. 

In  addition  to  the  doubtful  subprimary  homotypes  of  gamma 
and  eta,  there  are  two  rather  persistent  subprimary  setae :  theta,  which 
is  found  on  the  mesothorax  and  metathorax  of  both  suborders  and  on 
the  abdomen  of  Jugatae;  and  mu,  which  is  more  recent  and  appears 
only  on  the  abdomen  of  Frenatae. 

Subprimaries  of  less  common  occurrence  are  omega  and  phi  of  the 
Tau  group,  while  still  others  are  present  in  certain  families. 

Primary  or  primary  and  subprimary  setae  tend  to  associate  with 
each  other  in  groups.  These  groups  are  indicated  in  this  paper  by 
capital  letters. 

The  Beta  group  consists  of  alpha  and  beta;  Rho,  of  epsilon  and 
rho;  Kappa,  of  theta,  kappa,  and  eta;  Pi,  of  pi  and  nu;  and  Tau,  of 
tau,  omega,  and  phi.    On  the  abdomen  tau  is  associated  with  the  Pi  group. 

Both  primary  and  subprimary  setae  may  develop  into  tufts  borne  on 
verrucae.  The  verrucae  of  the  same  setal  group  tend  to  coalesce,  while 
those  of  different  groups  tend  to  remain  distinct. 

SYNONYMS 
In  the  following  tables  are  given  the  names  used  by  various  authors 
for  the  different  setae  on  the  segments  heretofore  studied.  A  parenthesis 
indicates  that  the  seta  is  subprimary  in  the  region  of  the  body  referred 
to.  "0"  indicates  that  the  seta  is  absent  from  that  region;  while  a 
dash  is  used  when  the  author  fails  to  mention  the  seta. 


40 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[40 


Mesothorax  and  Metathorax.     (Frenat^ve) 


alpha 

beta 

(gamma). 

delta 

epsilon 

rho 


(theta)- 
kappa — 

(eta) 

(mu) 

pi 

nu 

tau 

(omega), 
sigma 


Dyar,  1895 

ia 

ib 

o 

iia 
iib 
iii 
iv 

V 

o 
vi 

0 


viu 


Dyar,  1901 

i 
ii 


o 

iii 
iv 
va 

V 

vb 
o 
vi 
o 


Quail,  1904 
1 

ii 


0 

iii  a 

iii 

iv 

V 

vi 
o 

vii 
o 


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1  a 
ib 

X 

o 

iia 
iib 
iii 
iv 

V 

o 
vii 

o 
ix 

viii 


alphf 

beta. 

(gamma). 

delta 

epsilon — 
rho 


Muller,  1886 

Nymphalidae 

1st  stage 

1 

.  .  2 
0 
0 


(theta) 

kappa 

eta 

(mu) 

pi 

nu 

tau 

(omega)  „„ 
sigma 


0  — 


Abdomen 

ar,  1895 
renatae 

Dyar,  1901 
Frenatae 

Quail,  1904 
Frenatae 

Forbes, 
Frenatae 

1910 
Jugatae 

1 

1 

1 

1 

1 

U 

11 

11 

11 
X 
0 

11 

0 

0 

0 

0 

ma 



HI  a 

HI  a 

111  a 

111 

Ill 

111 

HI 

111 

0 

0 

0 

0 

IV 

IV 

IV 

IV 

IV 

V 

V 

V 

V 

V 

VI 

vi 

vb 

VI 

VI 

0 

Vll 

VI 

Vll 

vu 

Vll 

Vll 

VI 

Vll 

Vll 

Vll 

w\ 

VI 

Vll 

Vll 

Vll 

— 

— 

— 

IX 

IX 

\dii 

— 

— 

VIU 

Vlll 

41]  LEPIDOPTEROUS    LARVAE  — FRACKER  41 


PART  TWO.     SYSTEMATIC  OUTLINE  OF 
FAMILIES  AND  GENERA. 

A  complete  history  of  the  study  of  caterpillars  would  begin  with 
work  done  centuries  ago  and  would  include  the  names  of  many 
scientists.  It  would  necessarily  embrace  all  discussions  of  larvae  of  the 
Lepidoptera.  There  is  now  in  manuscript  a  list,  as  nearly  complete  as 
such  a  list  can  be  made,  of  all  published  papers  containing  descriptions 
of  immature  stages  of  American  members  of  this  order,  but  its  size  is  so 
great  that  arrangements  for  its  publication  are  difficult.  Nevertheless, 
no  object  would  be  served  here  by  an  extended  historical  account,  espe- 
cially as  the  results  obtained  by  the  older  workers  were  not  of  such  a 
nature  as  to  aid  materially  in  the  preparation  of  this  paper. 

The  period  from  Aristotle  to  the  last  quarter  of  the  nineteenth  cen- 
tury is  discussed  at  some  length  in  the  introduction  to  "Die  Schmetter- 
linge  Europas,"  the  third  edition,  edited  by  Arnold  Spuler.  Since  that 
time  the  subject  has  been  put  on  a  more  scientific  basis  by  the  work  of 
two  men.  Dr.  Harrison  G.  Dyar,  in  addition  to  the  papers  mentioned 
in  Part  One,  has  written  excellent  descriptions  of  new  larvae  for  various 
publications  every  year  for  a  quarter  of  a  century.  These  are  undoubt- 
edly the  best  descriptions  of  larval  Macroheterocera  extant,  for  they  give 
not  only  color  but  the  structural  characters  which  indicate  their  family 
and  sometimes  their  generic  position.  Since  1905  several  papers  have 
been  published  by  Dr.  W.  T.  M.  Forbes,  who  has  made  a  detailed  study 
of  the  head  sclerites,  mouth  parts,  and  prolegs  of  a  large  number  of 
species.  Representatives  of  all  the  more  important  families  of  Macro- 
lepidoptera  have  been  describexi  and  figured.  The  observations  of  Dyar 
and  Forbes  mark  the  first  advance  stride  toward  an  accurate  knowledge 
of  the  structure  and  relationships  of  the  larvae  of  this  order. 

In  spite  of  the  work  of  these  investigators  certain  gaps  remain  in 
our  knowledge,  especially  of  those  species  of  importance  to  economic 
entomologists.  The  most  conspicuous  of  these  is  our  ignorance  of  the 
structure  and  taxonomic  characters  of  the  larvae  of  the  Microlepidop- 
tera.     It  is  true,  as  one  author  puts  it,  that  **  there  seems  to  be  little 


42  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [42 

variation  in  these  forms,"  but  the  characters  are  present  and  their  ob- 
scurity merely  challenges  us  to  closer  search.  Another  demand  of  eco- 
nomic workers  is  an  analytical  key  to  the  families.  Dyar's  few  tables 
are  usually  not  adapted  to  the  identification  of  individual  specimens,  for 
he  uses  characters  which,  in  the  later  stages  of  many  species,  are  com- 
pletely obscured  by  secondary  setae  or  entirely  lost.  The  best  key  thus 
far  published  is  that  by  Forbes  (1910),  but  it  omits  nearly  all  the 
Microlepidoptera  as  well  as  the  more  obscure  families  of  the  larger  moths 
and  butterflies.  There  are  species  he  had  not  seen  which  trace  to  fami- 
lies in  which  they  do  not  belong,  but  such  a  fault  is  one  a  worker  on 
immature  insects  is  unable  to  avoid. 

In  several  respects  a  systematic  outline  of  larvae  differs  from  a 
classification  of  a  group  of  imagines.  It  is  clear  that  while  a  difference 
in  larval  characters  indicates  a  phylogenetic  divergence  just  as  surely 
as  does  a  variation  in  adult  structure,  similarity  in  the  adults  of  a  group 
of  genera  does  not  necessarily  indicate  the  presence  of  common  charac- 
ters in  the  larvae.  One  always  faces  the  fact  that  he  is  working  with 
genera  and  families  established  on  adult  characters  and  that  the  un- 
known species  of  a  particular  group  may  be  very  different  from  those 
with  which  he  is  acquainted. 

Another  element  of  doubt  is  caused  by  the  necessity  of  breeding. 
One  can  not  breed  a  specimen  and  keep  it  too.  Larvae  must  always  be 
identified  from  the  adults  into  which  their  associates  develop  except 
when  they  are  raised  from  fertilized  eggs  laid  by  a  known  female.  The 
danger  of  mistaken  records  can  be  greatly  reduced  by  careful  work  but 
when  handling  large  numbers  of  species  can  never  be  wholly  eliminated. 

It  should  also  be  noted  that  the  adult  state  represents  a  single  instar 
while  the  larva  undergoes  several  molts,  changing  materially  at  least 
once.  Wherever  possible  a  description  should  include  all  the  instars. 
In  this  paper,  only  the  more  mature  larvae  were  considered,  as  a  rule, 
but  in  most  families  the  characters  used  apply  to  all  except  the  first  or 
the  first  and  second  stages.  Usually  only  the  colors  change  after  the 
second  molt. 

These  sources  of  error  were  reduced  in  importance  by  the  confirma- 
tion of  observations  on  long  series  of  individuals.  The  larvae  of  several 
large  collections  were  examined,  with  the  result  that  several  mistakes 
due  to  these  causes  were  corrected. 

CHARACTERS   USED 

Adult  insects  are  identified  mainly  on  characters  of  the  wings,  seg- 
mented appendages,  body  sclerites,  copulatory  apparatus,  and  vestiture 
of  the  body  and  legs.     Of  these,  aU  except  the  segmented  appendages 


43]  LEPIDOPTEROVS    LARVAE  — FRACKER  43 

and  vestiture  are  either  absent  or  indistinguishable  in  lepidopterous 
larvae.  The  mouth  parts  and  antennae  of  all  but  a  few  species  are 
constructed  on  the  same  plan  and  show  such  limited  variation  that  little 
use  can  be  made  of  them.  No  one  has  yet  discovered  characters  of  much 
value  in  the  structure  of  the  thoracic  legs,  so  uniform  are  they  through- 
out the  entire  order.  The  vestiture  is  also  entirely  different  from  that 
of  other  insects.  It  is  consequently  necessary  to  seek  other  characters 
than  those  with  which  entomologists  are  usually  familiar  and  to  intro- 
duce new  terms  to  describe  them. 

The  structures  of  value  in  the  classification  of  these  larvae  are  pri- 
marily :  the  head  sclerites,  head  setae,  and  ocelli ;  the  armature  of  the 
body,  especially  the  setae ;  the  shape  of  the  spiracles ;  the  number  of 
prolegs  and  the  arrangement  of  the  crochets  they  bear ;  and  the  presence 
on  the  body  of  humps  and  gibbosities,  eversible  glands,  or  peculiar  modi- 
fications of  the  usual  organization.     These  will  be  taken  up  in  order. 

Head  parts. — The  varying  shapes  of  the  head  sclerites  and  positions 
of  the  setae  are  so  well  shown  by  Forbes  (1910)  that  they  need  little 
attention  here.  The  head  capsule  consists  almost  entirely  of  an  epicra- 
nium  divided  into  three  parts  by  the  forked  epicranial  suture.  These 
parts  are  the  right  and  left  sides  and  the  front.  The  latter  is  usually 
a  triangular  sclerite  on  the  facial  aspect  of  the  head.  To  its  ventral 
margin  is  attached  the  trapezoidal  clypeus  which  supports  the  labnim. 
Laterad  of  each  arm  of  the  epicranial  suture  is  a  narrow  area,  the  ad- 
frontal  piece  (afp,  Fig.  78),  the  exterior  indication  of  the  anterior  arm 
of  the  tentorium.  In  this  region  the  vai'ying  sizes  and  shapes  of  the 
front,  the  adfrontals,  and  the  labrum,  and  the  location  of  the  setae  they 
bear,  are  important  characters  for  identification. 

At  the  point  where  the  caudodorsal  part  of  the  head  capsule  joins 
either  the  prothorax  or  the  unchitinized  portion  of  the  head,  there  is  a 
pale  triangular  dorsal  area  of  thin  cuticula.  The  cephalic  point  of  this 
triangle  in  all  except  a  few  caterpillars  is  at  the  caudal  end  of  the  epi- 
cranial suture  and  its  sides  are  formed  by  the  caudad  projecting  lobes 
of  the  epicranium.  This  dorsal  area  is  known  as  the  ' '  vertical  triangle ' ', 
or  sometimes  merely  the  'Vertex",  although  the  latter  term  properly 
applies  to  the  dorsal  part  of  the  head  capsule  itself.  In  some  leaf- 
miners  the  front  extends  caudodorsad  as  far  as  this  triangle  and  the 
arms  of  the  epicranial  suture  do  not  unite  to  form  a  stem.  The  front 
in  such  cases  is  said  to  be  ''open".  In  very  small  larvae,  however,  care 
must  be  taken  in  determining  this  point,  for  microscopic  preparations 
show  the  tentorial  arms  much  more  distinctly  than  the  epicranial  suture, 
and  these  internal  arms  usually  do  not  meet  on  the  vertex.  The 
head  setae  are  numbered  according  to  Dyar's  scheme   (Figs.  78,  86). 


r 


44  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [44 

As  the  head  is  not  a  single  metamere  we  can  not  homologize  these  setae 
with  those  of  the  body  segments. 

The  ocelli  seem  to  form  one  of  the  most  satisfactory  characters  for 
the  separation  of  genera.  In  most  families  their  arrangement  and  the 
position  of  the  setae  associated  with  them  are  constant  in  long  series  of 
individuals  and  species.  Without  their  aid  the  difficulties  in  the  classifi- 
cation of  some  of  the  Microlepidoptera  would  be  almost  insurmountable. 
The  dorsal  four  usually  form  the  quadrant  of  a  circle,  with  the  other 
two  below  them  and  farther  apart.  (Figs.  70,  71.)  Beginning  at  the 
caudal  ocellus  of  the  dorsal  group  we  may  call  them  the  first  to  the 
fourth  in  regular  order.  The  fifth  is  caudoventrad  of  the  fourth  and 
in  some  cases  farther  ventrad  than  the  sixth  (Fig.  77)  which  is  the  one 
most  cephalic  in  position. 

Armature  of  the  body. — In  Part  One  it  was  shown  that  lepidopter- 
ous  larvae  have  certain  setae  in  a  definite  arrangement.  These  were 
denominated  by  Greek  letters  and  their  homotypy  was  studied  in  order 
that  any  particular  letter  might  be  made  to  apply  to  the  same  or  homo- 
typic  setae  on  every  segment  of  every  caterpillar.  For  that  study  it 
was  necessary  to  distinguish  between  primary  and  subprimary  setae,  the 
latter  being  missing  from  the  first  instar.  In  classification,  however, 
this  distinction  is  rarely  of  any  value,  and  as  subprimaries  are  few  in 
number  the  normal  ones  are  assumed  to  be  present  in  all  mature  larvae. 
A  statement  in  a  description  that  a  mature  larva  bears  primary  setae 
only,  is  to  be  interpreted  on  this  basis. 

The  more  conspicuous  forms  of  armature  are  usually  associated 
with  groups  of  setae.  "Tubercles",  "warts",  and  "spines"  are  terms 
now  in  use  describing  them.  The  first  has  the  disadvantage  of  meaning 
any  cuticular  projection  of  the  body  wall  from  a  minute  papilla  to  a 
conspicuous  prominence.  "Spines"  have  also  been  used  both  for  the 
projections  of  the  body  wall  and  for  the  branches  of  any  thorn-like 
process.  A  number  of  new  terms  are  therefore  suggested  for  particular 
kinds  of  armature.  Their  derivation  is  given  except  where  it  will  be 
perfectly  evident. 

In  the  most  generalized  larvae  a  seta  is  surrounded  at  the  base  by 
a  small  chitinized  ring,  very  slightly  raised.  This  ring  may  be  called  a 
papilla,  following  Scudder.  It  is  often  surrounded  by  a  small  and  defi- 
nitely bounded  chitinized  area  or  pinaculum  (L.  pinax,  dim.,  "a  small 
plate"),  such  as  is  seen  in  many  Microlepidoptera  (Figs.  15,  40).  When 
the  pinaculum  is  conspicuously  elevated  at  the  center  and  bears  the  seta 
on  a  distinct  projection,  it  may  be  termed  a  chalaza  (Gr.  ^a/.a!^a^ 
"pimple",  or  "tubercle"),  as  in  the  arctian  Utetheisa  (Fig.  90). 
Either  the  pinaculum  or  the  chalaza  may  be  double  or  triple,  and  may 


45]  LEPIDOPTEROUS    LARVAE  — FRACKER  45 

accordingly  bear  two  or  three  setae  (K,  fig.  39)  ;  but  neither  is  ever 
multisetiferous. 

When  the  setae  are  increased  in  number  new  modifications  are  to 
be  noted  in  the  cuticular  areas  to  which  they  are  attached.  The  most 
common  tendency  is  toward  the  development  of  tufts,  in  which  case 
each  tuft  is  said  to  be  borne  on  a  verruca  (L.  verruca,  "wart")  as 
shown  in  Fig.  88.  If  the  setae  are  so  thickly  grouped  as  to  form  a  dense 
upright  bundle,  the  term  verricule  (Fig,  91),  already  in  use  in  ento- 
mology, describes  their  condition.  In  some  cases  the  setae  are  increased 
in  number  on  a  pinaculum  without  forming  tufts,  as  on  the  prolegs  of 
notodontians  and  arctians  (Fig.  100).  As  the  term  plate  is  already  in 
use  for  this  structure  and  is  not  applied  to  other  different  conditions, 
it  is  adopted  here. 

More  conspicuous  than  verrucae  are  the  thorny  processes  bearing 
spine-like  setae,  found  in  saturnian  and  nymphalid  larvae  (Fig.  74), 
and  for  them  the  term  scolus  (Gr.  k«/  <  r,  "thorn")  is  particularly 
appropriate.  When  the  setae  are  borne  on  sharp  lateral  projections  of 
the  scolus,  these  projections  are  known  as  spinules. 

As  the  word  tubercle  has  been  applied  to  each  one  of  the  above 
structures  by  previous  writers,  it  is  deemed  best  to  retain  it  as  a  general 
term. 

Spiracles. — A  classification  of  larvae  based  on  the  spiracles  is  still 
unwritten.  It  is  to  be  hoped  that  some  future  investigator  will  study 
their  structure  and  report  the  variations  in  different  families.  As  yet 
little  use  can  be  made  of  them  altho  differences  in  their  shape,  location, 
and  formation  can  not  but  be  noted.  One  case  in  which  they  are  useful 
is  the  pyrali-zj'gaenoid  series  in  which  the  spiracles  become  smaller  and 
smaller  as  the  insects  become  more  and  more  specialized.  Certain  of 
these  families,  such  as  the  Pyromorphidae,  can  not  be  easily  distin- 
guished from  some  Bombycoidea  by  the  arrangement  of  their  verrucae, 
but  their  small,  circular  spiracles  are  very  different.     (Figs.  79,  104.) 

Prolegs. — Nearly  two  hundred  years  ago  Reaumur  figured  four  or 
five  forms  of  prolegs  and  the  hooks  attached  to  them.  He  made  no  use 
of  them  in  classification  but  the  figures  are  more  accurately  drawn  than 
those  of  most  later  workers.  Chapman  was  the  first  to  call  attention  to 
the  fact  that  the  crochets  of  Microlepidoptera  are  usually  arranged  in 
a  circle  while  those  of  the  Macros  are,  in  most  cases,  placed  in  a  single 
longitudinal  row. 

Prolegs  are  normally  present  on  segments  3,  4,  5,  6,  and  10  of  the 
abdomen,  one  pair  to  each  segment.  In  general  statements  only  the  first 
four  pairs  are  referred  to.    When  it  seems  necessary  to  distinguish  these 


46  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [46 

specifically  from  the  last  pair,  those  of  segment  10  are  known  as  the  anal 
prolegs  and  the  others  as  the  ventral. 

The  tip  of  the  proleg  on  which  the  hooks  or  crochets  are  borne  is 
called  the  planta.  In  the  most  generalized  forms  (e.  g.  Pseudauaphora, 
Hepialus)  this  planta  bears  a  complete  circle  of  well  developed  crochets 
surrounded  by  several  more  circles  of  smaller  ones.  In  Hepialus  the 
differences  between  the  inner  and  outer  are  not  as  marked  as  in  Pseudau- 
aphora (Fig.  96).  This  arrangement  is  a  multiserial  circle  and  is  con- 
fined to  Hepialidae,  Acrolophidae,  and  Yponomeutidae.  From  it  the 
crochets  may  be  lost  in  the  mesal  and  lateral  parts  of  the  circle  as  in 
Adela  (Fig.  94),  resulting  in  two  transverse  multiserial  hands,  which 
degenerate  in  Incurvaria  to  a  single  transverse  uniserial  band.  Where 
the  outer  circles  entirely  disappear  the  resulting  condition  is  known  as 
a  uniserial  circle  (Fig.  101),  for  the  crochets  are  in  a  single,  continuous 
series. 

The  uniserial  circle  has  the  bases  of  all  the  crochets  in  line  but  the 
lengths  are  seldom  uniform.  We  are  able  to  distinguish  uniordinal  cro- 
chets (Fig.  105),  in  which  the  tips  as  well  as  the  bases  are  in  a  straight 
line,  from  the  hiordinal  (Fig.  106),  in  which  the  crochets  are  of  two 
distinct  lengths  alternating.  Occasionally  triordinal  crochets  (Fig.  98) 
are  seen,  but  Forbes 's  separation  of  Rhopalocera  from  Heterocera  on 
this  basis  fails  tc  be  confirmed  by  observation.  In  fact  the  irregularities 
in  the  lengths  of  the  biordinal  crochets  make  any  extensive  use  of  the 
difference  in  the  number  of  sizes  inadvisable.  On  the  other  hand  the 
uniordinal  series  is  usually  definite,  and  the  irregularities,  except  at  the 
ends  of  the  row,  are  negligible. 

Having  a  complete  uniserial  circle  of  crochets,  a  group  may  develop 
transverse  bands  (Fig.  99)  by  the  loss  of  both  the  mesal  and  lateral 
parts  of  the  circle,  or  a  penelUpse  (L.  paene-\-ellipsis,  "almost  an  el- 
lipse") by  the  loss  of  only  a  short  portion  on  one  side.  The  penellipse 
may  be  lateral  as  in  Psychidae  (Fig.  85),  where  the  gap  in  the  series  is 
near  the  meson;  or  it  may  be  mesal  as  in  Pyraustinae  (Fig.  98),  where 
the  lost  crochets  were  farthest  from  the  meson. 

Finally  more  than  half  the  circle  may  be  lost  and  a  mesoseries 
(Fig.  105)  result.  This  is  the  arrangement  seen  in  nearly  all  the  Macro- 
lepidoptera  except  Hesperoidea.  In  certain  families  a  few  rudimentary 
hooks  remain  (or  are  secondarily  developed)  on  the  lateral  portion  of 
the  planta.  As  there  is  no  case  in  which  these  even  approach  the  size 
of  the  mesal  crochets  there  is  no  likelihood  of  this  condition,  to  which 
the  term  pseudocircle  (Fig.  97)  may  be  applied,  being  confused  with  a 
circle  or  penellipse. 

The  crochets  of  a  mesoseries,  penellipse,  or  circle  may  be  either  uni- 


47]  LEPIDOPTEROUS    LARVAE  — FRACKER  47 

ordinal  or  biordinal,  as  described  above.  In  addition,  aretians  and  a 
few  other  families  show  a  peculiar  specialization.  The  planta  (Fig. 
100)  is  longitudinally  extended  beyond  the  series  of  well  developed  cro- 
chets, which  in  these  cases  are  always  uniordinal.  At  each  end  of  this 
planta  is  a  row  of  much  smaller  chitinous  processes,  usually  not  hooked. 
These  are  often  so  slightly  developed  that  they  are  difficult  to  demon- 
strate, but  the  type  of  arrangement  is  easily  made  out  by  the  short  row 
of  crochets  on  the  elongated  planta.  We  may  apply  to  this  condition 
the  term  heteroideous  (Fig.  100)  now  used  by  botanists  for  ** diversified 
in  form".  In  distinction  from  this,  crochets  of  the  ordinary  mesoseries 
are  called  homoideous  (Fig.  105). 

Modifications,  not  well  covered  by  the  above  terms,  are  found  in 
Megalopygidae  and  Lycaenidae.  In  the  former  the  mesoseries  makes  a 
sharp  angle  cephalad  of  the  middle  while  the  crochets  near  the  angle 
are  as  short  as  those  at  the  ends  of  the  series.  The  genus  Carama  has  a 
distinct  gap  at  the  angle  so  that  the  hooks  are  in  two  groups.  In  some 
Lycaenidae  (Fig.  102)  there  is  a  similar  gap  near  the  middle  of  the 
series  and  from  the  planta  at  this  point  arises  a  small  fleshy  protu- 
berance. The  latter  is  present  in  all  members  of  the  family  altho  in 
many  genera  the  crochets  are  merely  shortened  opposite  it  instead  of 
being  wanting. 

Other  structures. — Certain  genera  and  families  show  peculiar  spe- 
cializations which  are  of  value  in  identification.  The  most  common  of 
these  are  eversible  glands,  or  osmateria,  such  as  are  used  in  distinguish- 
ing Papilionidae,  Parnassiidae,  and  Liparidae.  The  dorsal  gland  on  the 
seventh  abdominal  segment  of  Lycaenidae  is  also  said  to  occur  in  all 
species  but  is  so  minute  that  it  is  usually  overlooked.  The  ventral  pro- 
thoracic  glands  of  many  noctuids,  notodontians,  and  nymphalids  are 
conspicuous  enough  but  their  occurrence  does  not  usually  depend  upon 
family  or  generic  limits. 

Several  kinds  of  processes  of  the  body  wall  are  less  closely  associ- 
ated with  setae  than  are  seoli  and  verrueae.  The  most  common  of  these 
are  cornicula,  or  little  horns,  usually  heavily  chitinized.  They  are  very 
often  present  on  the  suranal  plate.  A  corniculum  is  similar  to  a  chalaza 
in  shape  but  does  not  bear  a  seta. 

Certain  slender  fleshy  processes  have  been  given  the  name,  "fleshy 
filaments",  by  former  authors,  and  that  term  describes  their  structure 
so  well  that  no  further  explanation  is  necessary.  They  vary  from  one 
to  many  pairs  and  are  found  in  all  Lymnadidae  (Fig.  92)  and  in  the 
papilionid  genus  Laertias. 

Other  projections  of  the  body  wall  are  described  in  connection  with 
the  larvae  which  bear  them.    Gibbosities  are  large  round  dorsal  swellings 


48  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [48 

more  like  malformations  than  processes.  Horns  are  sharp  pointed  and 
unbranched,  the  caudal  horn  of  the  sphingids  being  the  best  example. 
Protuberances  are  large  rounded  swellings  without  definite  outlines  and 
are  usually  lateral  in  position. 

There  are  two  or  more  large  chitinized  plates  covering  the  dorsal 
half  of  a  segment.  The  first  is  the  prothoracic  shield  (Figs.  7,  25,  etc.), 
a  thickening  of  the  cuticula  covering  the  greater  part  of  the  dorsal  half 
of  the  prothorax.  In  a  few  cases  shields  are  also  developed  on  segments 
II  and  9.  The  dorsum  of  segment  10  bears  the  suranal  plate,  which 
varies  from  a  mere  thickening  of  the  body  wall  to  a  highly  modified  and 
variously  specialized  structure.     (Fig.  84.) 

A  glossary  giving  all  these  terms  will  be  found  at  the  close  of  the 
paper.  Following  it,  the  method  of  numbering  the  segments  is  described 
and  a  list  of  the  Greek  letters  used  for  setae  is  given. 

CLASSIFICATION 

In  nomenclature  Dyar's  ''List  of  North  American  Lepidoptera" 
(1902)  has  been  followed  throughout.  While  this  list  is  not  perfect,  it 
is  widely  distributed  and  is  the  most  accurate  one  now  extant.  In  a 
few  cases  in  which  the  genus  has  been  divided  since  the  publication  of 
that  list  the  new  names  are  used  but  the  old  ones  are  included  in  paren- 
thesis. Certain  species  have  also  been  described  since  1902  and  they 
are  the  only  ones  'for  which  the  authority  is  given.  Outside  the  Micro- 
lepidoptera,  the  only  important  change  in  the  families  is  in  the  trans- 
ference of  Apatelodes  from  Notodontidae  to  Eupterotidae  and  in  the 
rearrangement  of  the  Saturnioidea. 

It  has  been  necessary  to  revise  the  Microlepidoptera  entirely,  owing 
to  a  rapid  advance  in  our  knowledge  of  the  adults.  The  grouping  and 
the  division  into  families  is  principally  a  compilation  from  Walsingham 
and  from  published  and  unpublished  work  of  August  Busck.  At  the 
same  time  we  believe  that  nothing  in  the  larval  structure  precludes  this 
arrangement  and  that  it  is  a  more  natural  classification  than  any  pub- 
lished more  than  a  decade  ago. 

The  order  of  treatment  is  the  reverse  of  that  usually  followed  in 
Lepidoptera.  There  seems  to  be  no  excuse  for  beginning  lists  and  out- 
lines of  this  order  with  the  most  specialized  forms  when  a  treatment  of 
Hymenoptera  always  starts  with  a  consideration  of  the  Tenthredinoidea, 
Coleoptera  with  the  Carabidae,  Diptera  with  the  Nematocera,  etc.  The 
latter  arrangement  is  the  logical  one  and  the  most  natural.  For  that 
reason  families  are  listed  here  in  an  order  which  proceeds  so  far  as 
possible  from  generalized  to  specialized.  In  most  cases,  consequently, 
it  is  the  exact  reverse  of  that  followed  in  Dyar's  List. 


49]  LEPIDOPTEROUS    LARVAE  — FR ACKER  49 

FAMILIES  OF  LEPIDOPTERA 

a.  Thoracic  legs  wanting  or  mere  fleshy  swellings, 
b.  Body  fleshy  and  swollen  at  middle,  fusiform;  front  closed  above. 

PRODOXIDAE 
bb.  Body  cylindrical  or  depressed,  never  fusiform, 

c.  Head  with  ocelli  of  each  side  either  six  in  number  or  reduced  to 
one ;  front  reaching  vertical  triangle, 
d.  Head  with  all  ocelli  small,  subequal  in  size. 

e.  Abdominal  segments  3,  4,  5,  and  6  with  rudimentary  prolegs, 
each  bearing  several  transverse  bands  of  crochets. 

TISCHERIIDAE 
ee.  Abdomen  either  without  prolegs  or  crochets  or  with  crochets 
on  segments  3,  4,  and  5.  GRACILARIIDAE 

dd.  Head  with  one  large  and  conspicuous  ocellus  on  each  side, 
e.  Ocelli  cephalic,  located  close  to  lateral  angles  of  clypeus; 
front  triangular  in  outline.  MICROPTERYGIDAE 

ee.  Ocelli  lateral,  distant  from  lateral  angles  of  clypeus;  front 
quadrangular, 
f .  Front  wider  at  caudal  end  than  at  cephalic ;  body  often  de- 
pressed and  moniliform;  prolegs  not  as  in  the  alterna- 
tive. GRACILARIIDAE 
ff.  Front  narrower  at  caudal  end  than  at  cephalic;  body 
always  cylindrical ;  segments  II  and  III  and  2  to  7  bear- 
ing prolegs  without  crochets  (Fig.  93).  (^^<^"?lt^f^i<^ 

NEPTICULIDAE 
cc.  Head  with  two  conspicuous  ocelli  on  each  side ;  front  not  reach- 
ing vertex.  HELIODINIDAE 
aa.  Thoracic  legs  present  and  segmented. 
b.  Prolegs  and  crochets  wholly  wanting. 

c.  Body  fusiform;  head  small  but  not  greatly  depressed;  front  not 
extending  to  vertical  triangle, 
d.  Intersegmental  incisions  indistinct ;  scoli  usually  present ;  body 

colored ;  size  large.  COCHLIDIIDAE  Sk-uI^'^Ua^ 

dd.  Intersegmental  incisions  distinct;  scoli  never  present;  body 
pale ;  size  very  small, 
e.  Kappa  and  eta  distant  or  all  setae  wanting.    PRODOXIDAE 
ee.  Kappa  and  eta  adjacent;  setae  small  but  distinct. 

GELECHIIDAE  ^ 
cc.  Body  usually  cylindrical,  always  very  small;  head  depressed 
but  not  narrowed ;  front  extending  to  vertical  triangle. 
'  COLEOPHORIDAE    ^ 


so  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [SO 

bb.  Prolegs  always  present,  when  reduced  represented  by   at  least 
rudimentary  crochets. 
c.  Body  bearing  neither  tufted  nor  secondary  setae;   prolegs  not 
bearing  more  than  four  setae  (pi,  nu,  tau,  and  sigma)    (Fig. 
101),  except  that  there  may  be  five  when  crochets  are  arranged 
in  a  multiserial  circle ;  mu  never  a  verruca,  never  associated  with 
additional  subprimaries. 
d.  Crochets  never  arranged  in  a  pseudocircle  (Fig.  97)  or  meso- 
series  (Fig.  105),  usually  in  a  circle  (Fig.  101)  or  penellipse 
(Fig.  98)   or  transverse  bands   (Fig.  99)  ;  epsilon  on  pro- 
thorax  always  below  alpha  and  gamma  (Fig.  7). 
e.  Prolegs  of  sixth  abdominal  segment  absent  or  without  cro- 
chets; larvae  small,  leaf -miners.  6RACILARIIDAE 
ee.  Prolegs  of  sixth  abdominal  segment  as  well  developed  as 
those  of  segments  3,  4,  and  5. 
f.  Kappa  group  on  prothorax  bisetose,  theta  absent    (Fig. 
43)  ;  crochets  never  multiserial. 
g.  Crochets  uniordinal,  arranged  in  a  complete  circle ;  body 
cylindrical;  Pi  group  on  mesothorax  unisetose. 

ORNEODIDAE 
gg.  Crochets  biordinal  (Figs.  98,  101),  except  when  body 
,  is  spindle-shaped  and  very  fleshy  and  when  Pi  group  on 
mesothorax  is  bisetose  (Fig.  50).        PYRALIDIDAE 
ff.  Kappa  group  on  prothorax  trisetose,  theta  present  (Fig. 
39). 
g.  Crochets  arranged  in  transverse  bands  (Fig.  99). 
h.  Crochets  arranged  either  in  a  single  transverse  row  or 
in  two  multiserial  bands  on  each  proleg. 

INCURVARIIDAE 
hh.  Crochets  always  arranged  in  two  uniserial  bands  on 
each  proleg. 
i.  Kappa  and  eta  of  abdomen  remote. 

BUCCULATRIGIDAE 
ii.  Kappa  and  eta  of  abdomen  adjacent  (Fig.  41). 
j.  Crochets  of  anal  prolegs  in  two  groups. 

GELECHIIDAE 
jj.  Crochets  of  anal  prolegs  in  a  single  transverse 
row. 
k.  Front  extending  about  one  third  of  the  distance 
to  the  vertical  triangle.  COSSIDAE 

kk.  Front  extending  at  least  two  thirds  of  the  dis- 
tance to  the  vertical  triangle. 


51]  LEPIDOPTEROUS    LARVAE  — FR ACKER  i\ 

I.  Spiracles  elliptical,  normal  in  size,  those  of 

segment  8  farther  dorsad  than  others. 

AEGERIIDAE  > 

II.  Spiracles  circular,  very  small,  the  pair  of 

segment  8  about  in  line;  crochets  of  right 
and  left  sides  usually   almost  continuous 
across  ventromeson.     COLEOPHORIDAE 
gg.  Crochets  arranged  in  a  circle  or  penellipse. 
h.  Kappa  and  eta  of  abdomen  remote  or  eta  wanting 
(Fig.  8). 
i.  Crochets  arranged  in  a  multiserial  circle  (Fig.  96) 
or  in  a  penellipse  (Fig.  98). 
j.  Setae  beta  of  prothorax  closer  together  on  dorsum 
than  setae  alpha;  crochets  always  in  a  multi- 
serial  circle.  ACROLOPHIDAE  .^ 
jj.  Setae  beta  on  prothorax  farther  apart  than  setae 
alpha, 
k.  Theta   absent   on    abdomen    (Fig.   37)  ;   beta, 
delta,  and  rho  distant  on  the  prothorax  (Fig. 
35);  crochets  sometimes  in  a  penellipse.         '-^.c^'U'  ]  4'k^ 

kk.  Theta  present  on  abdomen    (Fig.   6)  ;  beta, 
delta,  and  rho  adjacent  on  prothorax  (Fig.  5). 

HEPIALIDAE 
ii.  Crochets  arranged  in  a  uniserial  circle. 

j.  Prothorax  with  setae  of  Kappa  group  distant, 
about  as  far  from  spiracle  as  from  each  other; 
setae  alpha  of  abdomen  closer  together  than 
setae  beta.  LYONETIIDAE 

jj.  Prothorax  with  setae  of  Kappa  group  all  close 
together,  twice  as  far  from  spiracle  as  from 
each  other, 
k.  Setae  alpha  of  abdomen  much  farther  apart  on 

dorsum  than  setae  beta.  TINEIDAE  ' 

kk.  Setae  alpha  of  abdomen  not  farther  apart  on  , 

dorsum  than  setae  beta.      HELIODINIDAE  a^:-u.  r<s.J 
hh.  Kappa  and  eta  of  abdomen  adjacent  (Fig.  41) ;  cro-        (.^^^^ 
chets  in  a  uniserial  circle  or  penellipse. 
i.  Pi  group  of  mesothorax  bisetose  (Fig.  36). 

j.  Long  axis  of  prothoracic  spiracle  vertical;  setae 
alpha  of  segment  9  closer  together  than  setae 
beta.  THYRIDIDAB 


'CC'*-^~JLj 


52  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [52 

jj.  Long    axis    of    prothoracic    spiracle    horizontal 

(Fig.  69).  PSYCHIDAE 

ii.  Pi  group  on  mesothorax  unisetose  (Fig.  40)  ;  setae 

alpha  of  segment  9  farther  apart  than  setae  beta. 

j.  Setae  beta  closer  together  on  segment  9  than  on 

any  other  abdominal  segment,  usually  on  the 

KUlihJbUiiiLj.  ^^^®  ^^  adjacent  pinacula  (Fig.  42).  ( 

y     J  ^     ^^ ^  TORTRICIDAB 

//«tc-<rjn->M^<i<x  jj    getae  beta  at  least  as  far  apart  on  segment  9 

/l^n.jx^j^.tx\JyA^  as  on  other  abdominal  segments,  never  borne 

'  on    the  same  or  adjacent  pinacula  (Fig.  56). 

k.  Mandibles  large  and  conspicuous,  extending  far 
beyond  margins  of  labrum  (Fig.  72)  ;  larvae 
borers,  in  later  instars  very  large. 

COSSIDAE 
kk.  Mandibles  small,  larvae  leaf-feeders,  always 
small. 

I.  Coxae  of  metathoracic  legs  twice  as  far  apart 

as  wide ;  setae  indistinct,  prolegs  small. 

COSMOPTERYGIDAE 

II.  Coxae  of  metathoracic  legs  never  twice  as  far 

apart  as  wide, 
m.  Adfrontals  reaching  vertical  triangle  or 
nearly    so;    front   extending    two  thirds 
of  the  distance  to  the  vertical  triangle, 
when  shorter  forming  an  attenuate  point, 
or  head  not   depressed,   not  held  hori- 
zontally, 
n.  Crochets  biordinal  in  most  species;  ad- 
domen   with   alpha   and   beta   remote, 
segment  8  with  rho  never  caudodorsad 
of  spiracle. 
0.  Fourth  ocellus  much  closer  to  third 
than  to  sixth,  second  closer  to  third 
than  to  first.      OECOPHORIDAE* 
00.  Third  ocellus  not  so  closely  associated 
with  second  and  fourth. 

GELECHIIDAE* 
nn.  Crochets  uniordinal. 


♦Characters  separating  these  two  families  and  the  next  not  constant. 


5.^1  LEPIDOPTEROUS    LARVAE  — FRACKER  53 

o.  Abdomen  with  rho  of  segment  8  cau- 
dodorsad  of  spiracle,  alpha  and  beta 
remote.  BLASTOBASIDAE*  ^ 

00.  Abdomen  with  rho  of  segment  8  dor- 
sad or  cephalodorsad  of  spiracle, 
p.  Alpha    and   beta    of   abdomen   ad- 
jacent. (Schreckensteinia). 

YPONOMEUTIDAE 
pp.  Alpha  and  beta  of  abdomen   re- 
mote. HEMEROPHILIDAE 
mm.  Adf rontals  reaching  about  two  thirds, 
front  less  than  half,  the  distance  to  ver- 
tical triangle;  front  blunt  at  apex;  head 
depressed,  held  horizontally. 

STENOMIDAE 
dd.  Crochets  arranged  in  a  pseudocircle  (Fig.  97)  or  mesoseries 
(Figs.  100,  105). 
e.  Prothorax  with  Kappa  group  trisetose,  and  with  epsilon  be- 
low alpha  and  gamma,  not  near  rho  (Fig.  35). 
f .  Kappa  and  eta  of  abdomen  remote ;  crochets  uniordinal, 
sometimes  arranged  in  a  pseudocircle. 

YPONOMEUTIDAE 
ff.  Kappa  and  eta  of  abdomen  adjacent ;  crochets  arranged  in 
a  mesoseries. 
g.  Setae  beta  of  prothorax  about  as  far  apart  as  setae 

alpha ;  prolegs  usually  short.  ETHMIIDAE  ^ 

gg.  Setae  beta  of  prothorax  very  much  closer  together  than 

setae  alpha ;  prolegs  long  and  slender.  d  '   ^  '   i  i- 

HEMEROPHILIDAE  ^ru/^J'^m>i^ 
ee.  Prothorax  with  Kappa  group  bisetose,  and  with  epsilon  asso- 
ciated with  rho  between  delta  and  spiracle  (Fig.  21)  ;  kappa 
and  eta  of  abdomen  remote;  crochets  arranged  in  a  meso- 
series, usually  uniordinal. 
f.  Pi  group  on  mesothorax  and  metathorax  bisetose  (Fig.  50). 
r^  g.  Setae  small,  borne  on  minute  papillae.  THYATIRIDAE 
^  gg.  Setae  well  developed,  borne  on  chalazae. 
^    h.  Chalazae  rho  of  abdominal  segments  bisetose. 

LITHOSIIDAE 
hh.  Chalazae  rho  of  abdomen  unisetose  (Utetheisa). 

ARCTIIDAE 


♦Characters  separating  this  and  the  two  preceding  families  not  constant. 


54  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [54 

ff.  Pi  group  on  mesothorax  and  metathorax  unisetose   (Fig. 
22). 
g.  Body  without  conspicuous  gibbosities.       NOCTUIDAE 
gg.  Body  with  one  or  more  distinct  transverse  dorsal  gib- 
bosities; coloration  mainly  in  transverse  stripes. 

(AGARISTIDAE 

(NOCTUIDAE 

cc.  Body  bearing  tufted  or  secondary  setae  or  at  least  five  setae  on 

prolegs;  mu  usually  associated  with  several  other  subprimaries 

(Figs.  59  to  68)  ;  crochets  never  arranged  in  a  multiserial  circle. 

d.  Crochets  uniordinal  (Figs.  100, 105). 

e.  Number  of  pairs  of  ventral  prolegs  three  or  six. 

f.  Abdominal  segments  2  to  7,  inclusive,  bearing  prolegs, 
those  of  segments  2  and  7  without  crochets;  verrucae 
bearing  large  numbers  of  fine  setae. 

MEGALOPYGIDAE ' 
ft.  Abdominal  segments  2,  3  and  7  not  bearing  prolegs;  ver- 
rucae bearing  few  setae.  NOLIDAE 
ee.  Number  of  pairs  of  ventral  prolegs  four, 
f.  Verrucae  reduced,  or  obscured  by  development  of  secon- 
dary setae,  or  absent, 
g.  Head  muricate ;  ocelli  on  papillae,  the  third  very  large. 

AGAPETIDAE 
gg.  Head   smooth   or  nearly  so;   ocelli   sessile,   the   third 
normal, 
h.  Body  very  small,  hemispherical  in  shape;  head  re- 
tractile, minute ;  habit  parasitic ;  crochets  uniordinal, 
arranged  in  a  complete  circle.      EPIPYROPIDAE 
hh.  Body  cylindrical;  habits  not  parasitic. 

i.  Secondary   setae   numerous,    often    obscuring   both 
primary  setae  and  verrucae. 
j.  Spiracles  small,  circular  (Fig.  104)  ;  ventral  pro- 
legs  long,  slender  (Fig.  95). 

PTEROPHORIDAE 

jj.  Spiracles   elliptical,   well   developed    (Fig.   79)  ; 

ventral  prolegs  short  (Fig.  105). 

k.  Notch  of  labrum  deep,  with  parallel  sides  and 

rounded  bottom   (see  footnote,  p.  — )  ;  body 

often  bearing  tufts  and  pencils  of  setae  but 

never  with  cornicula.  NOCTUIDAE 

kk.  Notch  of  labrum  acute,  not  with  parallel  sides ; 

body  never  bearing  tufts  and  pencils  of 


55]  LEPIDOPTEROUS    LARVAE  — FRACKER  55 

setae  but  sometimes  with  cornicula. 

NOTODONTIDAE 
ii.  Secondary  setae  absent  or  sparse;  primary  setae 
always  distinct,  tho  sometimes  small, 
j.  Kappa  at  about  the  same  level  on  abdominal  seg- 
ments   6,    7,    and    8;    setae    very    small;    no 
humps,   horns,    or   minute   cuticular   processes 
present.     (Doa).  ARCTIIDAE 

jj.  Kappa  much  lower  on  segment  7  than  on  seg- 
ments 6  and  8  (Fig.  31). 
k.  Suranal  plate  terminating  in  an  acute  process 
and  anal  prolegs  wanting  (Fig.  89) ;  crochets 
in  a  pseudocircle  (Fig.  97). 

PLATYPTERYGIDAE  ^^APJo^muM 
kk.  Suranal  plate  rounded  posteriorly;    crochets 
in  a  mesoseries. 

I.  Body    covered    with    minute    cuticular    pro- 

cesses; form  cylindrical  except  for  a  dor- 
sal gibbosity  on  abdominal  segment  8;  no 
stemapoda  or  horns  present. 
1.  DIOPTIDAE 

II.  Body   not   covered   with   minute   processes; 

horns,    stemapoda,    or    gibbosities   usually 
present.  NOTODONTIDAE 

ff,  Verrucae  (Fig.  88),  at  least  mu,  well  developed,  distinct, 
bearing  many  setae ;  secondary  setae  sparse  or  absent  ex- 
cept on  prolegs. 
g.  Eversible  mediodorsal  glands  present  on  abdominal  seg-   ,  ♦  '•/ 

ments  6  and  7.  LIPARIDAE  /'J^"  ^-'"****^ 

gg.  Eversible  dorsal  glands  wanting, 
h.  Spiracles  large,  elliptical  (Fig.  79). 
i.  Verruca  kappa  in  about  the  same  position  on  ab- 
dominal segment  7  as  on  segments  6  and  8  (Figs. 
33,  67,  68)  ;  when    somewhat    lower,  mesothorax 
bearing  only  one  verruca  above  the  Kappa  group, 
j.  Mesothorax  bearing  only  one  verruca  above  Kappa    ,     / 

group  on  each  side.  SYNTOMIDAE   '^6U\^fM4AJ 

jj.  Mesothorax  bearing  two  verrucae  above  Kappa 

group  on  each  side  (Fig.  26).       ARCTIIDAE 

ii.  Verruca  kappa  much  lower  in  position  on  segment 

7  than  on  segments  6  and  8,  often  absent  or  fused 

with  verruca  eta  especially  on  segment  7   (Figs. 

65,  66). 


56  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [56 

j.  Crochets  homoideous  (Fig.  105)  ;  mesothorax 
bearing  two  verrucae  above  Kappa  group;  lab- 
rum  with  a  deep,  parallel-sided  notch. 

NOCTUIDAE 
jj.  Crochets    heteroideous   (Fig.  100)  ;    mesothorax 
usually  bearing  only  one  verruca  above  Kappa 
group;  verrucae  conspicuous,  altho  without  nu- 
merous setae.  PERICOPIDAE 
hh.  Spiracles  small,  circular  (Fig.  104). 
i.  Head  small,  retractile;  prolegs  short. 

PYEOMORPHIDAB 
ii.  Head  not  retractile;  prolegs  long,  slender,   cylin- 
drical (Fig.  95).  PTEROPHORIDAE 
dd.  Crochets  biordinal  or  triordinal  (Figs.  102,  106). 

e.  Setae  of  body  either  primary  or  tufted,  never  numerous  and 
secondary;  several  subprimaries  present  on  venter  or  on 
prolegs,  sometimes  rather  numerous  when  anal  prolegs  are 
wanting  or  ventral  prolegs  reduced  in  number  (Fig.  63). 
f.  Crochets  in  a  complete  circle  (Fig.  101). 

g.  Alpha  and  beta  of  abdomen  in  the  form  of  verrucae. 

( Scythris ) .  YPONOMEUTID  AE 

gg.  Alpha  and  beta  of  abdomen  single  setae ;  kappa  and 

eta  of  abdomen  adjacent.  LACOSOMIDAE 

ff.  Crochets  in  a  mesoseries  (Fig.  106)  or  pseudocircle  (Fig. 

97). 

g.  Suranal  plate  terminating  in  an  acute  process  and  anal 

prolegs  wanting  (Fig.  89)  ;  crochets  in  a  pseudocircle. 

PLATYPTERYGIDAE 

gg.  Suranal  plate  rounded  caudad;  anal  prolegs  present. 

h.  Number  of  pairs   of  ventral  prolegs  four,   all  well 

developed. 

i.  Kappa    group    on    prothorax    trisetose    (Fig.  39) ; 

kappa  and  eta  of  abdomen  adjacent. 

ETHMIIDAE 
ii.  Kappa    group    on    prothorax    bisetose   (Fig.  43)  ; 
kappa  and  eta  distant,  at  least  on  abdominal  seg- 
ments 4  to  8. 
j.  Prothorax  and  abdominal  segment  8  with  spira- 
cles twice  as  large  as  those  of  other  segments. 

EPIPLEMIDAE 


57]  LEPIDOPTEROUS    LARVAE— FRACKER  57 

jj.  Prothorax  and  abdominal  segment  8  with  spira- 
cles no  larger  than  those  of  other  segments. 

THYATIRIDAE 
hh.  Number  of  pairs  of  ventral  prolegs  reduced,  cephalic 
three  pairs  rudimentary  or  wanting. 

GEOMETRIDAE 
66.  Setae  of  body  secondary,  always  numerous  at  least  on  pro- 
legs;  anal  pair  and  four  ventral  pairs  of  prolegs  always 
present, 
f.  Secondary  setae  very  irregular  in  length,  very  long  setae 
mixed  with  others  a  tenth  as  long;  neither  distinct  ver- 
rucae  nor  scoli  ever  present;  body  often  bearing  latero- 
ventral,  blunt,  fleshy  protuberances, 
g.  Labrum  deeply  notched,  notch  acute,  either  reaching 
over  two-thirds  the  length  of  the  labrum  or  continued 
as  a  groove  which  reaches  clypeus ;  several  mediodorsal 
pencils  of  setae  often  present.  EUPTEROTIDAE 

gg.  Labrum  obtusely  notched;  notch  variable  but  never 
reaching  two-thirds  distance  to  base  of  labrum,  never 
continued  as  a  groove  which  reaches  clypeus. 

LASIOCAMPIDAE 
ff.  Secondary   setae   usually  short  and  uniform  in  length; 
when  long  and  irregular  either  distinct  verrucae  or  scoli 
are  present, 
g.  Body  usually  armed  with  a  mediodorsal  horn,  scar,  sco- 
lus,  or  pair  of  scoli  on  segment  8 ;  if  not,  head  produced 
into  a  high  conical  point;  scoli  never  present  on  head 
nor  on  dorsomeson  of  segments  1  to  7;  head  smooth; 
crochets  usually  only  biordinal. 
h.  Body  sphingiform,  never  bearing  even  rudimentary 
scoli  or  secondary  setae  above  level  of  prolegs. 
i.  Segments  divided  into  six  to  eight  annulets ;  prolegs 
not  widely  separated.  SPHINGIDAE 

ii.  Segments  not  divided  into  annulets ;  prolegs  widely 
separated.  BOMBYCIDAE 

hh.  Body  not  sphingiform,  always  bearing  at  least  rudi- 
mentary scoli.  SATURNIOIDEA 
gg.  Body  usually  not  armed  with  a  mediodorsal  horn,  scar, 
scolus  or  pair  of  scoli  on  segment  8;  when  so  armed, 
either  segments  4  to  7  also  bear  unpaired  mediodorsal 
scoli   or  the  head  is  conspicuously  bigibbous  above, 


58  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [58 

usually  bearing  a  pair  of  scoli  or  pointed  prominences ; 
crochets  usually  triordinal. 
h.  Crochets  arranged  in  a  circle,  usually  triordinal,  lat- 
eral crochets  about  as  well  developed  as  mesal;  sec- 
ondary setae  small  or  absent  on  dorsal  half  of  body, 
never  long  and  never  borne  on  scoli. 
i.  Head  much  larger  than  prothorax;  body  largest  at 
middle  distinctly  tapering  toward  both  ends. 

HESPERIIDAE 
ii.  Head  partially  retractile,  smaller  than  prothorax; 
body  cylindrical.  MEGATHYMIDAE 

hh.  Crochets  arranged  in  a  mesoseries  or  pseudocircle, 
lateral  crochets,  when  present,  rudimentary;  long 
setae  and  scoli  sometimes  present, 
i.  Prolegs  with  mesoseries  interrupted  or  reduced  at 
middle  and  with  a  narrow  spatulate  fleshy  lobe 
arising  near  the  interruption    (Fig.   102)  ;  head 
small, 
j.  Head  about  half  the  diameter  of  the  body. 

RIODINIDAE 

jj.  Head  usually  less  than  half  the  diameter  of  the 

body.  LYCAENIDAE 

ii.  Prolegs  without  a  fleshy  lobe  near  the  middle  of  the 

mesoseries. 

j.  Osmaterium  wanting. 

k.  Scoli   (Figs.  73,  74)   or  fleshy  filaments  (Fig. 
92)  well  developed  and  conspicuous  on  body; 
•    when  reduced,  large  scoli  present  on  head. 

I.  Mesothorax  and  sometimes  a  few  other  seg- 

ments bearing  fleshy  filaments;  secondary 
setae  short  and  confined  to  prolegs. 

LYMNADIDAB^U^'L'^ 

II.  Fleshy  filaments  never  present. 

m.  Scoli  at  least  twelve  times  as  long  as  wide, 
those  of  abdomen  as  long  as  metathorax 
is  wide ;  each  abdominal  segment  bearing 
three  scoli  on  each  side,  none  on  dorso- 
meson.  HELICONIIDAE 

mm.  Scoli  when  present  not  so  slender;  those 
of  abdomen  not  as  long  as  metathorax  is 
wide ;  mediodorsal  scoli  usually  present. 
NYMPHALIDAE 


59]  LEPIDOPTEROUS    LARVAE— FRACKER  59 

kk.  Scoli  never  present  on  head  or  body;  fleshy 
filaments  never  present. 

I.  Suranal  plate  bifurcate  at  tip,  bearing  two 

distinct  processes  (Fig.  84). 

AGAPETIDAE 

II.  Suranal  plate  rounded,  entire. 

m.  Crochets  in  a  pseudocircle  (Fig.  97)  ;  se- 
tae never  borne  on  chalazae ;  head  small. 
LIBYTHEIDAE 
mm.  Crochets  in  a  mesoseries. 

n.  Head  conspicuously  larger  than  protho- 
rax.  NYMPHALIDAE 

nn.  Head  not  larger  than  prothorax ;  setae 
usually  borne  on  chalazae. 

PIERIDAE 

jj.  Osmaterium  present  on  prothorax;  when  retracted, 

presence  shown  by  dorsal  groove  through  which 

it  is  everted. 

k.  Setae  minute,  never  borne  on  verrucae  except  in 

early  instars.  PAPILIONIDAE 

kk.  Setae  well  developed;  some  verrucae  present. 

PARNASSIIDAE 


60  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [60 


SUBORDER  JUOATAE 

SUPERFAMILY  MICROPTERYGOIDEA 

The  association  of  the  Hepialidae  with  the  Micropterygidae  dates 
from  Comstock's  work  on  wing  venation  in  1893.  Since  that  time  they 
have  usually  been  placed  together  in  a  separate  suborder  from  all  other 
moths  and  butterflies.  There  seem  to  be  no  larval  structures,  however, 
which  unite  the  two  families.  Dyar  (1895b)  after  studying  both  Mi- 
cropteryx  and  Eriocephala,  as  well  as  Hepialus,  concludes  that,  "there 
is  nothing  to  contradict  placing  Mieropteryx  with  Hepialus  in  the  sub- 
order Jugatae"  and  that  ''there  seems  to  be  nothing  to  preclude  a  deri- 
vation of  Eriocephala  from  Mieropteryx";  but  these  statements  are 
hardly  definite  enough  to  convince  one  of  the  relationships  of  the  genera 
in  the  absence  of  constructive  evidence. 

Family  Hepialidae 

The  larvae  of  several  European  species  of  Hepialus  will  be  found 
described  in  Part  One.  (See  Figs.  2-6,  13,  14.)  In  addition  it  should 
be  mentioned  here  that  the  ocelli  are  not  in  a  semicircle  but  are  in  two 
vertical  rows  of  three  each  and  that  the  crochets  of  the  ventral  prolegs 
are  in  a  complete  multiserial  circle,  while  those  of  the  anal  pair  are 
similar  but  are  nearly  or  quite  interrupted  caudally.  Sthenopis  is  an- 
other American  genus  of  this  family  but  no  larvae  have  been  seen  by 
the  writer. 

Family  Micropterygidae 

The  larvae  of  only  one  species  of  this  family  have  been  examined. 
The  setae  are  almost  or  entirely  indistinguishable.  Thoracic  and  abdom- 
inal legs  are  wholly  wanting  and  the  head  is  strongly  depressed.  The 
body  is  thickest  at  the  prothorax  and  gradually  diminishes  posteriorly, 
the  anal  segment  having  a  very  small  diameter.  The  front  extends  to 
the  large  vertical  triangle.  Close  to  the  cephalic  end  of  each  arm  of  the 
epicranial  suture  is  a  single  large  ocellus. 

Epimartyria  auricrinella  was  the  species  seen. 


61]  LEPIDOPTEROUS    LARVAE  — FRACKER  61 


SUBORDER  FRENATAE 

MICROLEPIDOPTERA 

Altho  much  abused,  the  term  Microlepidoptera  is  a  convenient  one 
to  indicate  the  smaller  members  of  the  Heterocera.  The  limits  of  the 
group  are  not  now  and  never  can  be  fixed,  for  the  division  is  not  an 
entirely  natural  one.  Used  here  to  cover  the  same  families  that  Dyar's 
List  includes  in  "TINEOIDEA",  it  embraces  three  or  more  wholly 
separate  groups,  no  more  closely  related  to  each  other  than  some  of  them 
are  to  the  Macrolepidoptera. 

The  following  is  an  outline  of  the  classification  used  in  this  paper. 
The  sources  from  which  it  was  drawn  and  the  reasons  for  departing 
from  Dyar's  arrangement  are  given  in  the  introduction  to  Part  Two. 
It  is  followed  by  a  brief  discussion  of  the  larval  characters  which  bear 
on  the  relationships  of  the  group. 


Aculeata 

Nepticulidae 
Prodoxidae 
Incurvariidae 
Tischeriidae 


Non-aculeata 

a.    Tineoid  series 

Tineoidea 
Acrolophidae 
Tineidae 
Bucculatrigidae 
Lyonetiidae 

Yponomeutoidea 
Heliodinidae 
Yponomeutidae 

Gracilariidae 

Tortricidae 

Thyrididae 

Aegeriidae 

Cossidae 


62  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [62 

Psychidae 
Elachistidae 
Coleophoridae 
Gelechioidea 

Ethmiidae 

Stenomidae 

Hemerophilidae 

Gelechiidae 

Oecophoridae 

Blastobasidae 

Cosmopterygidae 

b.     Pyrali-zygaenoid  series 
Pyralidoidea 

Pyralididae 

Orneodidae 

Pterophoridae 
Zygaenoidea 

Chalcosidae 

Pyromorphidae 

Epipyropidae 

Dalceridae 

Megalopygidae 
..  Cochlidiidae 

Position  uncertain 

Lacosomidae 
Nolidae 
(    

Aculeata.  The  four  small  families  included  here  are  so  reduced  in 
size  and  structure  that  a  classification  of  them  based  on  larvae  would 
require  special  preparation  and  a  special  set  of  characters.  It  is  prob- 
able that  the  tentorium  will  be  found  to  yield  important  evidence  on  the 
relationships  of  the  families  to  each  other  and  to  other  leaf -miners,  such 
as  the  Gracilariidae.  In  all  the  species  the  crochets  are  wanting  or  in 
rudimentary  transverse  bands.  The  arrangement  of  the  setae  seems 
in  most  cases  to  be  indistinguishable.  The  group  Aculeata  is  based,  as 
yet,  wholly  on  adult  structure.  While  both  adults  and  larvae  are  special- 
ized by  reduction,  the  presence  of  aculei,  on  which  the  group  is  based, 
is  a  generalized  character.  The  larval  structure  of  the  various  species 
is  described  on  a  later  page. 

Non-aculeata.  This  general  term  comprises  all  micros  without  acu- 
lei on  the  wings.  On  the  basis  of  larval  structure  scarcely  a  single 
character  unites  them  to  each  other.    The  most  constant  distinctions  are 


63]  LEPIDOPTEROUS    LARVAE  — FRACKER  63 

in  the  chaetotaxy  of  the  prothorax.  On  Pseudanaphora,  as  on  Hepialus, 
the  setae  rho  and  epsilon  are  as  far  apart  as  alpha  and  beta  or  nearly  so. 
In  Aegeriidae,  many  Tortricidae  and  others,  rho  has  migrated  forward 
and  has  become  associated  with  epsilon  below  alpha  and  gamma.  One 
or  the  other  of  these  two  conditions  is  present  in  all  the  Micros.  In 
Macrolepidoptera,  on  the  other  hand,  epsilon  has  retreated  caudad  while 
rho  retains  its  primitive  position  below  beta  and  delta.  This  character, 
so  far  as  I  know,  has  no  exceptions  in  those  forms  which  bear  primary 
setae  only. 

A  definite  and  clear  distinction  is  also  found  in  the  Kappa  group 
in  front  of  the  prothoracic  spiracle.  In  the  Macros  this  group  consists 
of  two  setae,  kappa  and  eta,  while  all  Micros  except  Pyralidoidea  and 
Zygaenoidea  have  three,  theta  being  added. 

The  crochets  also  furnish  useful  characters,  varying  greatly  in  the 
more  generalized  half  of  the  order  but  being  nearly  always  arranged 
in  a  mesoseries  or  pseudocircle  in  the  more  specialized  moths  and  butter- 
flies.   Again  the  Zygaenoidea  must  be  excepted. 

A  point  to  which  Dyar  called  attention  twenty  years  ago  is  the  close 
relation  of  kappa  and  eta  ("iv"  and  "v")  on  the  abdomen  and  this 
comes  close  to  covering  the  Microlepidoptera  as  here  limited.  But  ap- 
parently this  was  not  the  generalized  condition  at  all.  Nearly  all  Lepi- 
doptera  have  descended  from  species  which  would  now  be  included  in 
the  families  Hepialidae,  Micropterygidae,  Acrolophidae,  Tineidae,  and 
Yponomeutidae,  and  yet  all  these  families  have  kappa  and  eta  separated, 
much  as  in  Noctuidae. 

The  following  seems  to  be  the  best  explanation  of  the  conflicting 
characters  mentioned  above: 

The  setae  of  the  ancestor  of  all  Non-aculeata  were  arranged  very 
much  as  in  Tineidae  and  Acrolophidae.  (Figs.  7,  8,  15,  16.)  Kappa 
on  the  prothorax  was  a  trisetose  group,  epsilon  was  located  below  alpha 
and  gamma  and  not  associated  with  rho,  kappa  and  eta  on  the  abdomen 
were  wholly  distinct,  and  the  crochets  were  in  a  complete  circle,  probably 
multiserial.  Gradually  evolution  of  this  arrangement  resulted  in  three 
main  divisions,  of  which  it  is  now  impossible  to  tell  which  is  the  oldest. 

One  of  these  divisions  (Figs.  39-42)  retained  theta  on  the  prothorax, 
but,  above  the  most  generalized  forms,  kappa  and  eta  became  associated 
on  the  abdomen  and  all  sorts  of  modifications  took  place  in  the  develop- 
ment of  crochets.  In  these  forms  epsilon  keeps  its  original  position  while 
rho  is  likely  to  be  found  in  any  location  back  of  it.  The  members  of 
the  Tineoid  series  possess  this  variable  set  of  characters  and  are  often 
honored  with  the  name  of  "true  Micros"  in  contradistinction  to  the 
pyralids  and  zygaenids. 


64  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [64 

A  second  group  (Figs.  43-46)  was  distinguished  by  the  loss  of  theta 
on  the  prothorax  and  the  association  of  kappa  and  eta  on  the  abdomen 
while  epsilon  remained  below  alpha  and  gamma  on  the  prothorax  and 
the  crochets  remained  in  a  complete  circle.  The  Pyralidoidea  and  prob- 
ably the  Zygaenoidea  have  originated  from  these  forms  and  have  retained 
all  three  distinctive  characters  except  that  the  crochets  have  gradually 
been  reduced  in  number  and  groups  of  adjacent  setae  have  been  modified 
into  tufts. 

In  the  third  primary  division  (Figs.  21-24  et  al.),  theta  was  lost  on 
the  prothorax  and  epsUon  migrated  back  to  rho  to  cover  the  opening, 
kappa  and  eta  remained  distant  on  the  abdomen,  and  the  crochets  be- 
came so  limited  in  number  as  to  reach  less  than  half  way  round  the  pro- 
leg,  forming  a  mesoseries.  From  this  division  have  arisen  all  the  true 
Macroheterocera,  i.  e.,  all  the  Macrolepidoptera  except  the  Rhopalocera. 

Family  Nepticulidae 

The  immense  number  of  species  in  the  genus  Nepticula  causes  one 
to  hesitate  to  make  generalizations  concerning  the  family.  Many  of  the 
larvae  have  been  seen  by  entomologists,  but  very  few  species  are  familiar 
to  the  writer.  Descriptions  in  most  cases  neglect  to  state  whether  legs 
are  present  on  the  thorax  or  crochets  on  the  abdomen,  whether  the  body 
is  moniliform,  depressed  or  cylindrical,  and  what  is  the  shape  of  the 
front,  altho  they  seldom  fail  to  report  whether  the  body  is  white  or 
greenish  white  and  that  the  head  is  brown. 

In  all  the  species  of  Nepticula  examined,  and  in  those  described  by 
"Wood  (1894),  both  crochets  and  segmented  thoracic  legs  are  wanting; 
there  are  two  pairs  of  fleshy  leglike  swellings  on  the  thoracic  segments  and 
six  pairs  on  the  abdomen  (Fig.  93) ;  the  head  is  flattened  but  compressed 
rather  than  depressed;  the  front  is  narrowed  caudad;  the  lobes  of  the 
epicranium  extend  caudad  to  a  considerable  distance  behind  the  meeting 
point  of  the  front  and  vertical  triangle ;  and  there  is  a  single  large  and 
conspicuous  ocellus  on  each  side. 

Ectoedemia  oirutella,  E.  phleophaga,  and  Opostega  nonstrigeUa 
were  also  examined  and  show  a  similar  structure  except  that  the  proleg- 
like  swellings  seem  to  be  absent.  A  careful  study  of  the  entire  head 
capsule  and  the  tentorium  will  be  necessary  before  these  forms  can  be 
intelligently  classified. 

Family  Prodoxidae 

The  two  well-known  species  of  this  family  differ  markedly,  having 
but  three  or  four  readily  observed  characters  in  common.  The  head  is 
not  depressed  as  in  many  Aculeata,  but  is  about  as  high  as  wide  and  is 


65]  LEPIDOPTEROUS    LARVAE  — FRACKER  65 

considerably  smaller  than  the  prothorax.  The  arms  of  the  epicranial 
suture  unite  near  the  vertical  triangle  to  form  a  stem  which  separates 
the  front  from  the  triangle.  A  third  character  is  the  lack  of  crochets, 
which  seems  strange  in  caterpillars  of  this  size.  The  body  is  round  and 
fleshy,  and  wider  in  the  middle  than  at  the  ends. 

Pronuha  yuccasella  possesses  thoracic  legs  and  swellings  represent- 
ing abdominal  prolegs,  the  latter  present  on  segments  3,  4,  5,  and  6. 
These  proleg  swellings  are  not  found  on  those  Gelechiidae,  Coleophori- 
dae,  and  Cochlidiidae  which  are  similar  enough  to  cause  confusion. 

Prodoxus  quinquepunctella  is  without  legs  or  leglike  swellings  of 
any  kind,  but  the  closed  front  is  sufficient  to  distinguish  it  from  such 
other  legless  larvae  as  have  the  body  similarly  shaped.  An  undescribed 
species  from  agave  in  Arizona  was  also  examined  and  was  found  to  be 
very  similar. 

Family  Incurvariidae 

The  larvae  of  this  family  are,  in  some  respects,  nearly  as  generalized 
as  any  members  of  the  order.  While  it  is  perhaps  an  open  question  as 
to  whether  the  common  progenitor  of  Aculeata  possessed  a  front  which 
was  closed  above  by  the  union  of  the  arms  of  the  epicranial  suture  or  open 
to  the  vertical  triangle,  the  conditions  in  other  insects  and  in  the  Microp- 
terygidae  incline  one  to  the  former  view.  This  would  place  Adela 
and  Incurvaria  closer  to  the  common  ancestor  of  all  Frenatae  than  the 
Nepticulidae. 

Head  as  high  as  broad,  not  retractile;  front  reaching  about  two- 
thirds  of  the  distance  to  the  vertical  triangle;  adfrontals  extending  to 
vertical  triangle.  Body  cylindrical,  intersegmental  incisions  shallow  or 
indistinct;  thorax  with  setae  in  the  usual  position  but  those  dorsad  of 
kappa  indistinct;  abdomen  with  kappa  and  eta  adjacent,  close  to  and 
caudad  of  ventral  edge  of  spiracle ;  mu  and  Pi  group  as  usual ;  thoracic 
legs  present;  prolegs  indicated  only  by  the  crochets  which  are  in  trans- 
verse bands  on  segments  3,  4,  5,  and  6. 

Adela  viridella  and  A.  degeerella  of  Europe  have  the  short  and  rudi- 
mentary crochets  arranged  in  two  transverse  multiserial  bands  (Fig.  94). 
Forbes  considers  this  condition  to  represent  the  beginning  of  crochets 
in  Lepidoptera,  but  it  is  much  more  probable  that  such  an  arrangement 
is  merely  a  reduced  form  of  the  multiserial  circle  found  in  Hepialus 
larvae.  An  unidentified  American  species  from  Vermont  was  also  ex- 
amined and  in  it  the  crochets  were  similar. 

Incurvaria  koerneriella  has  but  one  uniserial  row  of  very  rudiment- 
ary crochets  to  represent  each  proleg.  This  is  undoubtedly  a  degenerate 
condition. 


66  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [66 

Family  Tischerddae 

This  family  is  a  highly  specialized  group  of  Aeuleata  and  its  simi- 
larity to  the  Gracilariidae  has  usually  caused  it  to  be  placed  with  them. 
The  presence  of  crochets  in  the  total  absence  of  thoracic  legs  occurs  only 
in  these  two  families. 

Head  strongly  depressed,  three  to  six  times  as  long  as  high;  front 
extending  to  caudal  margin  of  head,  but  usually  narrowed  caudad  to  a 
point ;  ocelli  six  in  number,  uniform  in  size.  Body  distinctly  monilif orm 
as  seen  from  above,  strongly  depressed;  thoracic  legs  wanting;  abdomi- 
nal segments  3,  4,  5,  and  6  with  each  proleg  represented  by  a  pair  of 
short,  transverse,  uniserial  rows  of  very  small  uniordinal  crochets. 

Tischeria  malifoliella,  T.  complanella,  and  other  species  of  this  genus 
are  common  blotch-miners.  The  front  is  wider  at  the  caudal  than  at  the 
cephalic  end. 

Coptotriche  zelleriella  is  similar  but  less  common.  The  front  is  nar- 
rowed caudad  to  a  point. 

SUPERFAIVIILY  TINEOIDEA 

It  is  with  regret  that  this  superfamily  name  is  used,  for  the  word 
may  mean  almoi^t  anything.  But  the  group  which  includes  Tinea  must 
receive  the  above  title,  however  ambiguous  the  word.  In  the  sense  em- 
ployed here  the  superfamily  includes  less  than  half  of  the  genera  included 
by  Dyar  in  Tineidae.  The  necessity  for  this  change  is  explained  in  the 
introduction  to  the  Microlepidoptera  on  a  preceding  page. 

Characters  of  the  larvae  which  show  the  relationship  of  the  three 
families  included  here. are:  first,  the  trisetose  Kappa  group  on  the  pro- 
thorax;  second,  the  distance  by  which  kappa  and  eta  are  separated  on 
the  abdomen;  third,  the  triangular  front  which  is  not  open  dorsad; 
fourth,  the  location  of  beta  on  the  prothorax,  where  it  is  closer  to  the 
dorsomeson  than  alpha. 

Family  Acrolophidae 

The  Acrolophidae,  or  Anaphorinae  as  they  have  been  called,  include 
some  of  the  largest  and  most  primitive  of  the  Microlepidoptera.  In 
addition  to  the  structures  common  to  the  four  tineoid  families,  Acrolo- 
phidae are  differentiated  by  a  multiserial  circle  of  crochets  (Fig.  96) 
and  may  be  easily  separated  from  Bucculatrigidae  and  Tineidae  by  the 
large  size  and  the  fact  that  kappa  on  the  prothorax  is  more  closely 
associated  with  theta  near  the  spiracle  than  with  eta  in  the  more  cephalic 
and  more  usual  position  (Fig.  7).  Pseudanaphora  arcanella  was  the  only 
species  examined. 


67]  LEPIDOPTEROUS    LARVAE  — FRACKER  67 

Family  Tineidae 

In  this  paper  the  Tineidae  include  only  a  few  genera  closely  related 
to  Tinea,  such  as  Tineola  and  Scardia.  They  distinctly  show  the  char- 
acters given  for  the  superfamily  Tineoidea  but  differ  strikingly  from 
the  other  three  families  in  the  following  combination  of  characters:  the 
setae  alpha  on  the  abdominal  segments  are  farther  apart  than  the  setae 
beta,  the  crochets  are  uniordinal  and  are  arranged  in  a  complete  uni- 
serial  circle,  and  the  three  setae  forming  the  Kappa  group  on  the  protho- 
rax  are  close  together. 

Scardia  fiskeella  (Figs.  51  to  54)  was  the  only  species  examined  of 
which  the  material  was  entirely  satisfactory,  altho  Tineola  hisselliella 
was  also  seen. 

Family  Bucculatrigidae 

Systematists  have  come  to  think  of  the  genus  Bucculatrix  as  a 
chronic  obstacle  to  the  satisfactory  classification  of  the  lower  Micros. 
It  has  been  driven  "from  pillar  to  post"  and  the  end  is  not  in  sight. 
The  situation  usually  consists  in  the  positive  denial  of  admittance  to  the 
particular  family  which  an  investigator  is  studying.  The  author  erects 
a  new  family  for  the  genus,  first,  because  specialists  on  adult  Microlepi- 
doptera  will  not  admit  the  validity  of  placing  Bucculatrix  in  any  one 
of  the  recognized  families ;  second,  because  the  larvae  can  not  be  closely 
associated  with  those  of  any  other  genus  of  which  specimens  have  been 
examined.  The  diagnostic  characters  of  Bucculatrix  koehelella  are  as 
follows : 

Head  about  as  high  as  wide,  not  elongate,  bearing  primary  setae 
only;  front  reaching  about  two-thirds,  adfrontals  all  the  way,  to  the 
vertical  triangle.  Body  cylindrical,  intersegmental  incisions  moderate. 
All  setae  in  the  position  usual  in  Mierolepidoptera,  except  that  on  the 
abdomen,  kappa  and  eta  are  widely  separated  and  at  about  the  same 
level,  and  that  alpha  is  below  the  level  of  beta  on  segments  8  and  9. 
Spiracles  circular.  Prolegs  slender  and  rather  long,  present  on  segments 
3,  4,  5,  6,  and  10,  the  ventral  ones  each  bearing  two  transverse  bands  of 
uniordinal,  well-developed  crochets,  the  anal  pair  bearing  a  single  trans- 
verse band. 

Family  Lyonetiidae 

The  small  size  and  generalized  but  obscure  characters  of  this  family 
make  the  genera  and  species  difficult  to  distinguish.  It  is  often  almost 
impossible  to  make  out  locations  of  setae,  arrangement  of  ocelli,  and 
other  points  ordinarily  of  value. 


68  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [« 

Head  more  or  less  depressed;  front  triangular,  not  extending  to 
vertical  triangle  in  American  species;  boundaries  of  adfrontals  extend- 
ing to  the  vertical  triangle  on  each  side ;  first  and  second  ocelli  usually 
nearly  contiguous,  second,  third,  and  sixth  in  a  vertical  row  cephalad 
of  the  fifth.  Body  cylindrical,  incisions  moderate.  Prothorax  with  the 
Kappa  group  trisetose,  the  three  setae  widely  separated.  Abdomen  with 
alpha  much  closer  to  dorsomeson  than  beta,  rho  located  immediately 
above  spiracle,  kappa  some  distance  caudad  of  spiracle,  and  eta  between 
kappa  and  spiracle  but  located  farther  ventrad,  or  in  some  cases  appar- 
ently wanting.  Thoracic  legs  present ;  prolegs  present  on  segments  3,  4, 
5,  and  6,  each  bearing  a  complete  uniserial  circle  of  uniordinal  crochets. 

The  above  list  of  characters  was  drawn  from  specimens  of  Bedellia 
somnulenteUa  and  verified  from  Proleucoptera  smUacieUa,  the  only  other 
American  species  seen.  Leucoptera  (Cemiostoma)  spartifolieUa  of 
Europe  differs  from  them  in  the  front,  which  reaches  the  vertical  tri- 
angle, and  in  the  crochets,  which  are  biserial  in  the  caudal  half  of  the 
circle. 

SUPERFAIVOLY  YPONOMEUTOIDEA 

Still  retaining  the  ancestral,  generalized  arrangement  of  setae,  the 
few  forms  included  in  the  Yponomeutoidea  share  with  the  Tineoidea 
the  distinction  of  being  closely  similar  to  Hepialus  and  the  primitive 
type.  Altho  a  small  group,  the  structure  is  extremely  varied  in  those 
characters  which,  in  specialized  forms,  are  constant  in  entire  superfami- 
lies.  There  are  two  families  each  of  which  includes  larvae  of  at  least 
two  strikingly  different  forms.  Some  authors  consider  Hemerophilidae 
and  Ethmiidae  as  relatives  of  this  group  but  the  larval  structure  indi- 
cates a  closer  union  with  Gelechioidea.  The  same  is  true  of  the  genus 
Schreckensteinia. 

Family  Heliodinidae 

It  is  clear  that  the  "elachistid"  genera  now  included  here  are  more 
closely  related  to  Yponomeutidae  than  to  any  other  families  of  the  order. 
Kappa  and  eta  of  the  abdomen  are  distant,  the  Kappa  group  of  the 
prothorax  is  trisetose,  with  the  three  setae  close  together,  and  the  front 
extends  somewhat  over  half  the  distance  to  the  vertical  triangle  in  some 
species  and  reaches  that  triangle  in  others;  the  spiracle  is  small  and 
circular. 

Lithariapteryx  dbroniaeeUa.  Head  scarcely  depressed;  front  short. 
Abdomen  with  kappa  and  eta  not  on  the  same  swelling,  alpha  directly 
cephalad  of  beta.  Crochets  long,  uniordinal  or  biordinal,  arranged  in 
a  complete  circle. 


69]  LEPIDOPTEROUS    LARVAE  — FR ACKER  69 

Antispila  nyssaefoUella  and  Aspidiscus  sp.  (?).  Head  strongly- 
depressed  ;  front  extending  to  vertical  triangle ;  two  pairs  of  ocelli  large 
and  conspicuous,  the  others  reduced.  Thoracic  and  abdominal  legs  want- 
ing. Abdomen  with  kappa  and  eta  distinctly  separated  but  both  on  the 
same  swelling. 

Family  Yponomeutidae 

Like  the  Pterophoridae  this  family  is  difficult  to  diagnose  on  ac- 
count of  the  great  variation  among  the  different  genera  it  includes.  At 
the  same  time  there  is  little  or  no  overlapping  with  other  families.  All 
Yponomeutidae  except  Scythris  and  Schreckensteinia  have  beta  below 
the  level  of  alpha  on  the  prothorax,  the  Kappa  group  trisetose  on  the 
prothorax,  and  kappa  and  eta  distant  on  the  abdomen.  No  other  larvae 
possess  this  combination  of  characters.  The  Tineoidea  are  the  closest 
and  constitute  the  principal  reason  for  introducing  the  alpha-beta  char- 
acter above.  In  view  of  this  definite  combination  of  setal  characters  and 
the  great  variation  in  other  particulars  no  general  description  is  given 
for  the  family. 

Schreckensteinia  in  the  larval  stage  seems  to  be  more  closely  related 
to  Gelechioidea  than  to  Plutellinae,  where  the  more  recent  authorities 
place  it.  In  addition  to  the  characters  given  in  the  following  table  this 
genus  may  be  distinguished  by  the  prolegs,  which  are  long  and  slender 
and  at  the  tip  bear  from  four  to  six  crochets  in  a  circle. 

The  subfamilies  may  be  separated  as  follows : 

a.  Prolegs  longer  than  wide ;  crochets  uniserial,  either  biordinal  or  uni- 
ordinal ;  Pi  group  on  metathoi»,x  represented  by  a  single  seta. 

Plutellinae 
aa.  Prolegs  wider  than  long ;  crochets  various. 

b.  Body  bearing  numerous  setae  on  verruca-like  plates ;  Pi  group  con- 
sisting of  four  to  eight  setae  on  each  abdominal  segment. 

SCYTHRIDINAE 

bb.  Body  bearing  primary  setae  only;  Pi  group  never  bearing  more 
than  two  setae  on  thoracic  or  three  on  abdominal  segments. 

Yponomeutinae 

Following  are  partial  keys  to  the  genera : 

Plutellinae 

a.  Abdomen  with  kappa  and  eta  remote,  alpha  and  beta  remote. 

b.  Crochets  arranged  in  a  pseudocircle.  Plutella 

bb.  Crochets  arranged  in  a  mesoseries.  Cerostoma 

aa.  Abdomen  with  kappa  and  eta  adjacent,  alpha  and  beta  adjacent. 

Schreckensteinia 


70  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [70 

Scythridinae 

a.  Crochets  biordinal,  arranged  in  a  complete  uniserial  circle.    Scythris 

Yponomeutinae 

a.  Pi  group  on  metathorax  consisting  of  two  setae. 

b.  Crochets  arranged  in  a  mesoseries.  Mieza 

bb.  Crochets  arranged  in  a  multiserial  circle.  Atteva 

aa.  Pi  group  on  metathorax  consisting  of  a  single  seta ;  crochets  arranged 
in  a  multiserial  circle, 
b.  Cephalic  seta  of  Kappa  group  on  prothorax  ventrad  of  the  other 
two. 
c.  Beta  ventrad  of  alpha  on  metathorax;  segment  9  with  a  dorsal 
shield  bearing  setae  alpha,  beta,  rho,  kappa,  and  eta. 

Zelleria 

cc.  Beta  caudad  of  alpha  on  metathorax.  Swammerdamia 

bb.  Cephalic  seta  of  Kappa  group  on  prothorax  dorsad  of  the  other 

two ;  beta  caudoventrad  of  alpha  on  metathorax.         Yponomeuta 

The  following  species  of  Yponomeutidae  were  examined : 
Plutella  maculipennis  Cerostoma  ruirella 

Schreckensteinia  erythriella  Scythris  magnatella 

Mieza  igninix     '  Atteva  aurea 

Zelleria  gracilariella  Swammerdamia  pyrella  (Europe) 

Yponomeuta  plumhella,  Y.  multipunctella 

Family  GRACiLARnDAE 

The  gracilarians  form  one  of  the  most  definitely  bounded  families 
of  the  order.  Whether  examined  in  an  early  or  a  late  instar,  they  are 
distinct  from  the  larvae  of  other  moths.  This  is  true  in  spite  of  the  fact 
that  a  complete  change  of  structure  takes  place  at  the  second  or  a  later 
molt.  Before  this  molt  the  mandibles  are  horizontal  and  wheel-shaped, 
and  toothed  like  a  buzz-saw.  No  such  structure  is  known  elsewhere. 
The  distinctive  feature  of  the  later  instars  is  the  presence  of  but  three 
pairs  of  ventral  prolegs,  located  on  segments  3,  4,  and  5.  It  should  be 
noted  that  where  the  number  of  prolegs  is  reduced  in  other  families,  as 
in  some  Noctuidae,  Geometridae,  and  Nolidae,  they  are  always  present 
on  segment  6  and  are  first  lost  on  segment  3.  The  prolegs  of  gracilarian 
larvae  are  very  short  and  are  often  not  represented  by  swellings  at  all 
but  their  location  is  shown  by  suckers  or  by  crochets  which  are  arranged 
in  various  ways.  Thoracic  legs  may  be  present  or  wanting.  The  setae 
are  so  minute  that  their  position  usually  can  not  be  determined  satisfac- 
torily. 


71]  LEPIDOPTEROUS    LARVAE  — FRACKER  71 

Three  subfamilies  are  recognized,  of  one  of  which  specimens  have 
not  been  available. 

Gracilariinae.  Head  as  high  as  wide,  shape  normal;  front  not 
reaching  vertical  triangle.  Body  cylindrical,  intersegmental  incisions 
shallow.  Thoracic  legs  present ;  crochets  of  prolegs  arranged  in  a  lateral 
penellipse  enclosing  a  transverse  series,  all  uniordinal  (Fig.  103).  Gra- 
cilaria  consimUella,  G.  violacella,  and  Ornix  geminatella  were  examined ; 
and  Coriscium,  the  only  other  genus,  is  described  as  being  similar. 

Lithocolletinae.  Head  depressed,  strongly  narrowed  cephalad; 
front  with  subparallel  sides,  extending  to  vertical  triangle  and  often 
widest  at  caudal  margin  of  head.  Body  depressed,  moniliform.  Thora- 
cic legs  present  or  wanting;  ventral  prolegs  reduced,  either  bearing 
transverse  rows  of  crochets  or  modified  into  suckers,  present  on  segments 
3,  4,  and  5. 

Lithocolletis  hamadryadella,  L.  ostensackenella,  Marmara  salictella, 
M.  fulgidella,  and  Cameraria  sp.  (?)  were  studied.  In  Marmara  both 
thoracic  legs  and  crochets  are  present,  while  in  Cameraria  neither  could 
be  identified.  The  individuals  of  Lithocolletis  varied  in  this  regard.  It 
is  to  be  noted  that  in  many  cases  legs  are  acquired  at  the  last  molt  and 
that  a  persistent  study  of  all  stages  will  be  necessary  before  the  different 
genera  can  be  distinguished  with  any  assurance  of  accuracy. 

Family  Tortricidae 

The  family  of  leaf-rolling  caterpillars  is  a  remarkably  uniform  and 
generalized  one.  Larval  structure  indicates  rather  close  relationship 
with  both  Cossidae  and  Gelechioidea  but  is  not  to  be  relied  upon,  for  all 
these  groups  are  typical  Mierolepidoptera  in  most  respects  and  may  be- 
long to  wholly  different  but  only  slightly  specialized  stocks.  Individual 
fiuctuating  variations  are  rather  confusing  in  an  attempt  at  classification 
but  all  specimens  seen  will  trace  to  the  family  except  an  occasional 
aberrant  one.  Greater  difficulties  are  met  in  working  with  the  genera. 
For  example,  about  twenty  percent  of  codling  moth  larvae  have  mu  of 
segment  9  located  on  the  same  pinaculum  with  kappa  and  eta  and  will 
therefore  not  trace  to  Cydia.  The  writer  has  not  found  absolutely  con- 
stant characters  to  distinguish  the  genera  of  this  family  but  hopes  that 
the  synopsis  given  here  will  suggest  other  and  possibly  better  means  of 
separation.  The  larvae  are  of  sufficient  economic  importance  to  warrant 
the  expenditure  of  considerable  time  in  the  study  of  their  structure. 

Head  not  depressed ;  front  extending  from  one-fourth  to  three- 
fourths  of  the  distance  to  the  vertical  triangle ;  adfrontals  usually  touch- 
ing the  vertical  triangle;  ocelli  six,  variously  arranged,  but  the  sixth 
always  rather  close  to  the  fourth  and  fifth.     Body  cylindrical  or  sub- 


72  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [72 

moniliform,  sometimes  depressed  in  early  but  rarely  in  later  instars. 
Setae  of  thorax  and  abdomen  as  in  Figs.  39  to  42  except  as  noted  for 
particular  genera ;  rho  directly  cephalad  of  spiracle  on  segment  8  except 
in  a  few  rare  cases.  Spiracles  broad-elliptical  in  outline,  somewhat 
larger  and  farther  dorsad  on  eighth  than  on  preceding  segments.  Pro- 
legs  always  present  on  segments  3,  4,  5,  6,  and  10,  first  four  pairs  each 
bearing  a  complete  circle  of  uniordinal  or  biordinal  crochets. 

It  will  be  noted  that  the  subfamily  Olethreutinae  (Grapholithinae) 
is  not  accepted  here,  as  no  larval  characters  were  found  to  justify  it. 
The  genera  included  under  this  name  probably  do  not  form  a  natural 
group.    The  other  two  subfamilies  may  be  distinguished  as  follows : 

a.  Abdomen  with  kappa  and  eta  in  a  horizontal  line  or  nearly  so;  seg- 
ment 7  with  Pi  group  unisetose ;  prothorax  with  delta  close  to  and 
ventrocephalad  of  beta;  crochets  uniordinal,  sessile,  poorly  devel- 
oped. Phaloniinae 

aa.  Abdomen  with  kappa  and  eta  in  a  diagonal  or  vertical  line ;  segment 
7  with  Pi  group  at  least  bisetose ;  prothorax  with  delta  ventrad  or 
ventrocaudad  of  beta,  sometimes  distant.  Tortricinae 

Genera  of  Tortricinae : 

a.  Segment  9  with  alpha  close  to  rho  and  usually  situated  on  the  same 
pinaculum  with  it,  not  associated  with  beta  (Fig.  42). 
b.  Mu  absent  on  segment  9  (as  in  Fig.  56)  ;  setae  located  on  black  and 
heavily  chitinized  pinacula ;  crochets  uniordinal.  Sciaphila 

bb.  Mu  present  on  segment  9,  usually  associated  with  kappa  and  eta. 
c.  Adfrontals  extending  all  the  way  and  front  about  two-thirds  of 
the  way  to  the  vertical  triangle. 
d.  Arms  of  epicranial  suture  concave  in  dorsal  third,  meeting  in 
an  attenuate  point, 
e.  First  abdominal  segment  with  kappa  and  eta  in  a  diagonal 
line;  seventh,  in  a  horizontal  line  (as  in  Fig.  45). 

Thiodia 

ee.  First  abdominal  segment  with  kappa  and  eta  in  a  nearly. 

vertical  line  (as  in  Fig.  41)  ;  seventh,  in  a  diagonal  line. 

f.  Mu  on  segment  9  located  on  the  same  pinaculum  with 

kappa  and  eta  (as  in  Fig.  46).  Tmetocera 

(In  part)     Exartema 

ff.  Mu  usually  not  located  on  the  same  pinaculum  with  kappa 

and  eta  (Fig.  42).  Cydia 

dd.  Arms  of  epicranial  suture  straight  in  dorsal  third,  meeting 

in  a  regularly  narrowed  point.  Eucosma 


73]  LEPIDOPTEROUS    LARVAE  — FRACKER  73 

ec.  Adfrontals  extending  two  thirds  and  front  about  one  half  the 
distance  to  the  vertical  triangle.  Pseudogalleria 

aa.  Segment  9  with  alpha  as  distant  from  rho  as  from  beta  (as  in  Fig. 
38)  and  with  mu,  kappa,  and  eta  present  on  one  pinaculum  (as  in 
Fig.  46). 
b.  Pi  group  consisting  of  only  two  setae  on  abdominal  segment  7  and 
often  only  one  on  segment  8,  Alceris 

bb.  Pi  group  trisetose  on  abdominal  segment  7  and  bisetose  on  seg- 
ment 8. 
c.  Middle  seta  of  trisetose  Kappa  group  on  prothorax  dorsad  of  the 
other  two.  Epagoge 

cc.  Middle  seta  of  Kappa  group  on  prothorax  ventrad  of  or  in  line 
with  the  other  two. 
d.  Middle  seta  of  Kappa  group  on  prothorax  at  least  three  times 
as  far  from  caudal  as  from  cephalic  seta, 
e.  Mesothorax  and  metathorax  with  Pi  group  bisetose   (as  in 
Fig.  50).  Archips  (a) 

ee.  Mesothorax    and    metathorax    with    Pi    group    unisetose 
(Fig.  40) 
f.  Second  ocellus  much  farther  from  first  than  from  third. 
(Fig.  80).  Platijnota 

Archips  (b) 
ff.  Second  ocellus  as  close  to  first  as  to  third  (Fig.  71). 

Ancylis 

Olethreutes 

Tortrix 

Episimus 

Cenopis 

dd.  Middle  seta  of  Kappa  group  on  prothorax  not  more  than 

twice  as  far  from  caudal  as  from  cephalic  seta. 

e.  Fourth  ocellus  much  closer  to  third  than  to  sixth  and  caudad 

of  line  joining  third  and  sixth.  Ecdytolophia 

ee.  Fourth  ocellus  about  half  way  between  third  and  sixth  and 

in  line  with  them.  (Fig.  70).  Enarmonia 

Lord  Walsingham  in  a  recent  volume  of  the  Biologia  Centrali- 
Americana  changes  to  some  extent  the  generic  location  of  species  in  the 
Tortricidae.  Three  of  his  transfers  are  adopted  here,  the  former  genus 
names  being  included  in  parenthesis;  but  in  several  other  instances,  the 
change  does  not  seem  to  be  supported  by  the  evidence  of  larval  structure. 
The  following  were  the  species  examined: 


74  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [74 

PHALONHNAE. 

Phalonia  Mlarana  (Europe) 

TORTRICINAE 

Sciaphila  wahlbomiana  (Europe) 

Thiodia  arctostaphylana 

Exartema  malana,  E.  exoletum 

Tmetocera  ocellana 

Cydia  pomonella,  C.  (Melissopus)  latiferreanus,  C.  saltitans 

Eucosma  pulsatillana,  E.  scudderiana,  E.  (Proteopteryx)  wil- 

lingana  Kearf. 
Pseudogalleria  inimicella 

Alceris  minuta,  A.  hastiana,  A.  foliana,  A.  hrittania  Kearf. 
Epagoge  sulphureana,  E.  caryae 
Archips  (a)  cerasivorana,  A.  fervidana,  A.  parallela 
Archips  (b)  argyrospila,  A.  negundana,  A.  rosaceana 
Platynota  labiosana 

Olethreutes  niveiguttana,  0.   (Eudemis)   vacciniana 
Ancylis  comptana,  A.  divisana,  A.  nuheculana 
Tortrix  fumiferana,  T.  quercifoliana,  T.  citrana 
Episimus  argutanus 

Cenopis  directana  Walk.,  C.  pettitana  Eobsn. 
Ecdytolaphia  insiticiana 
Enarmonia  caryana,  E.  nehritana,  E.  prunivora 

Family  Thyrididae. 

Head  smaller  than  prothorax,  bearing  primary  setae  only;  ocelli 
six,  arranged  in  a  regular  semicircle;  labrum  moderately  emarginate; 
front  reaching  more  than  half  way  to  vertical  triangle.  Body  regu- 
larly cylindrical;  intersegmental  incisions  shallow.  Prothorax  with  a 
shield  bearing  rho  near  epsilon  below  alpha  and  gamma ;  Kappa  group 
trisetose.  Mesothorax  and  metathorax  with  Pi  group  bisetose.  First 
eight  abdominal  segments  with  alpha  farther  laterad  than  beta,  epsilon 
absent  or  very  minute,  kappa  and  eta  borne  on  the  same  pinaculum. 
Pi  group  consisting  of  two  setae  on  segment  1,  three  setae  on  segments 
2  to  6,  two  setae  on  7,  one  seta  on  8;  abdominal  segment  9  with  alpha 
closer  to  dorsomeson  than  beta  (Fig.  55).  Prolegs  with  biordinal 
crochets  in  a  complete  circle ;  anal  prolegs  with  transverse  series  of  cro- 
chets.   Spiracles  elliptical,  small. 

The  above  characterization  was  made  from  Thyris  fenestrella  of 
Europe  and  Dysodia  oculatana  of  America,  the  chaetotaxy  of  the  two 
being  constant.  The  bisetose  Pi  group  of  the  last  two  thoracic  segments 
and  the  arrangement  of  the  setae  on  segment  9  of  the  abdomen  will  dis- 


75]  LEPIDOPTEROUS    LARVAE  — FRACKER  75 

tinguish  this  family  from  all  others.  The  affinities  are  clearly  with  the 
true  Microlepidoptera,  not  with  the  Zygaenoidea  or  Bombyeoidea. 

Thyris  differs  from  Dysodia  in  the  shape  of  the  front,  which  in  the 
former  is  nearly  as  broad  as  high,  with  adfrontals  bounded  by  straight 
lines,  while  in  Dysodia  it  is  long  and  narrow  with  nearly  parallel  sides 
and  the  adfrontals  are  widened  above. 

Three  other  genera  with  unknown  larvae  are  recorded  from  North 
America,  in  addition  to  Thyridopyralis.  The  latter  does  not  belong 
in  this  family.  As  the  name  indicates,  the  imaginal  characters  conflict, 
but  those  of  the  larva  clearly  place  T.  gallaerandalis,  the  only  species, 
in  Pyralididae,  subfamily  Phycitinae.  The  pyralid  structures  are  the 
bisetose  Kappa  group  of  the  prothorax,  the  unisetose  Pi  group  of  the 
other  thoracic  segments,  and  the  position  of  alpha  on  segment  9  where 
it  is  farther  laterad  than  beta. 

Family  AEGERiroAE. 

Sesiidae,  the  name  used  in  Dyar's  List  for  this  family,  is  the  one  by 
which  it  is  best  known,  but  as  it  has  been  discarded  in  all  the  more 
recent  systematic  work,  there  seems  to  be  no  reason  for  continuing  the 
error.  It  appears  to  be  clearly  established  that  Sesia  belongs  in  Sphing- 
idae  and  that  Aegeria  is  the  oldest  genus  in  the  family. 

The  larvae  are  well  known  borers  and  at  least  two  of  them  are 
serious  and  very  common  enemies  of  the  peach.  All  are  so  uniform 
that  their  separation  is  difficult.  A  key  to  the  known  species  has  been 
published  by  Dyar  (Beutenmiiller,  1900).  The  one  given  below  is  based 
on  practically  the  same  species  but  employs  different  characters,  and  it 
is  hoped  that  later  workers  will  add  to  the  number  of  good  generic 
distinctions  as  well  as  to  the  number  of  known  larvae.  The  following 
characters  are  common  to  all  the  species: 

Head  smaller  than  prothorax,  with  strong  mandibles;  front  and 
ocelli  various;  labrum  shallowly  concave  at  tip.  Body  cylindrical, 
incisions  rather  deep.  Prothorax  with  beta  farther  mesad  than  alpha 
and  with  Kappa  group  trisetose,  mesothorax  and  metathorax  as  in 
Tortricidae  (Fig.  40).  Abdomen  with  kappa  and  eta  adjacent  and 
other  setae  as  usual  except  that  they  are  disarranged  on  segment  8  by 
the  change  in  the  position  of  the  spiracle ;  segment  9  with  all  setae  in  a 
single  transverse  row  (Fig.  57).  Spiracles  broad  and  elliptical,  much 
larger  and  higher  on  eighth  than  on  other  abdominal  segments.  Prolegs 
always  bearing  two  transverse  bands  of  uniordinal  crochets  (Fig.  99). 

Genera  of  Aegeriidae : 


76  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [76 

a.  The  three  caudodorsal  ocelli  forming  a  triangle  with  an  acute  angle 
at  the  second  ocellus  (Fig.  77) ;  seta  kappa  on  metathorax  at  least 
two  and  one-half  times  as  far  from  eta  as  from  theta.* 
b.  Vertical  triangle  longer  than  wide,  touching  adfrontals. 

Vespamima 
bb.  Vertical  triangle  broadly  rounded,  wider  than  long,  usually  not 
touching  adfrontals. 
c.  Crochets  not  more  than  nine  in  number,  large  and  thick;  setae 
large  and  distinct.  Parharmonia 

cc.  Crochets  usually  over  ten  in  number,  when  fewer  they  are  small 
and  slender;  setae  reduced, 
d.  Adfrontals  uniform  in  width,  sides  straight  or  convex. 

Sanninoidea* 
dd.  Adfrontals  strongly  narrowed  near  frontal  seta,  margins  sin- 
uate, concave  in  part  of  their  course.  Aegeria 
aa.  The  three  caudodorsal  ocelli  forming  a  triangle  always  with  an 
obtuse  angle  at  the  second  ocellus  (Fig.  75)  ;  seta  kappa  of  meta- 
thorax never  more  than  twice  as  far  from  eta  as  from  theta. 
b.  Spiracles  of  eighth  abdominal  segment  located  subdorsally,  at  least 
six  times  as  far  apart  as  each  is  wide ;  annulets  distinct. 
c.  Crochets  fifteen  to  eighteen  in  a  row;  adfrontal  margins  touch- 
ing vertical  triangle.                                                         Podosesia 
cc.  Crochets  less  than  fifteen  or  more  than  eighteen  in  number; 
adfrontals  usually  not  touching  vertical  triangle.     Memythrus 
bb.  Spiracles  of  segment  8  located  on  the  dorsum,  less  than  four  times 
as  far  apart  as  each  is  wide ;  annulets  indistinct ;  setae  very  small. 

Melittia 

The  following  species  were  studied  in  arranging  the  above  table: 

Vespamima  sequoiae 

Parharmonia  pini 

Sanninoidea  exitiosa,  S.  opalescens 

Aegeria  ( Synanthedon)  pictipes,  A.  rutilans,  A.  castaneae 

Podosesia  syringae 

Memythrus  polistiformis,  M.  rohinae,  M.  tricinctus,  M.  irillians 

Melittia  satyriniformis 

In  addition,  Dyar  in  the  paper  referred  to   above  describes  the 
following : 


*Each  species  of  Sanninoidea  differs  somewhat  from  one  or  the  other  of  the 
two  characters  included  in  "a";  both  characters  must  therefore  be  tried. 


77]  LEPIDOPTEROUS    LARVAE  — FRACKER  77 

Bemhecia  marginata.  Crochets  very  small,  ten  to  fifteen  in  a  row; 
spiracles  slightly  chitinized ;  setae  strongly  developed ;  segments  triannu- 
late;  adfrontals  not  reaching  vertical  triangle. 

Alcathoe  caudata.  Similar  to  Bembecia  except  that  the  crochets 
are  larger  and  are  heavily  chitinized. 

Family  Cossidae. 

The  Carpenter  moths  received  their  popular  name  from  the  larval 
habit  of  boring  in  trees.  This  form  of  life  has  modified  the  structure, 
especially  of  the  head,  and  has  caused  the  development  of  rather  heavily 
chitinized  pinacula  for  relatively  reduced  setae.  Many  of  the  species 
attain  considerable  size  and  their  larvae  are  some  of  our  largest 
caterpillars. 

Head  broad,  usually  longer,  if  not  higher,  than  wide,  smaller  than 
prothorax  to  which  it  is  closely  united;  front  varying  from  one  third 
to  one  half  height  of  head;  dorsal  four  ocelli  forming  nearly  a  semi- 
circle distant  from  the  fourth  and  fifth ;  labrum  truncate  at  tip,  with  a 
scarcely  perceptible  emargination ;  mandibles  very  large.  (Fig.  72.) 
Body  widest  at  prothorax,  narrowest  at  beginning  of  abdomen,  bearing 
primary  setae  only.  Prothorax  with  rho  directly  caudad  of  epsilon, 
Kappa  group  trisetose.  Mesothorax  and  metathorax  as  in  Tortricidae 
(Fig.  40).  Abdomen  with  kappa  and  eta  adjacent;  epsilon  usually  pres- 
ent cephalad  of  spiracle,  sometimes  large;  beta  above  level  of  alpha  on 
segment  9.  Prolegs  present  on  segment  3,  4,  5,  6,  and  10;  crochets 
various. 

Genera  of  Cossidae: 

a.  Crochets  uniordinal,  arranged  in  two  transverse  bands;  prothorax 
bearing  a  large,  dorsal,  semicircular,  rugose  plate  on  its  caudal  half ; 
spiracles  of  segment  8  two  or  three  times  as  large  as  those  of  seg- 
ments 1  to  7  and  located  much  nearer  dorsomeson.  Cossula 
aa.  Crochets  biordinal  or  triordinal,  arranged  in  a  complete  circle, 
b.  Prothoracic  shield  with  the  caudal  margin  smooth  and  not  elevated ; 
spiracle  of  segment  8  in  line  with  those  of  segments  1  to  7,  below 
rho. 
c.  Setae  alpha  of  middle  abdominal  segments  only  two-thirds  as  far 
apart  on  dorsum  as  setae  beta.                                 Prionoxystus 
cc.  Setae  alpha  of  middle  abdominal  segments  more  than  three- 
fourths  as  far  apart  as  setae  beta  (in  American  species). 

Cossus 

bb.  Prothoracic  shield  with   the   dorsal  half  of  the  caudal  margin 

conspicuous  and  strongly  rugose;  spiracle  of  segment  8  higher 

than  those  of  segments  1  to  7,  caudad  of  rho.  Zeuzera 


78  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [78 

Cossula  magnifica  is  so  different  from  other  cossid  larvae  that  at 
first  it  seems  to  deserve  the  rank  of  a  separate  subfamily.  Certain 
European  larvae  form  a  series  connecting  this  type  with  the  others,  hence 
such  a  division  could  not  be  defended.  For  example,  in  Phragmatoecia 
castaneae  Hiibner,  the  crochets  are  uniordinal  but  arranged  in  a  com- 
plete circle  and  the  last  pair  of  spiracles  are  enlarged  and  moved  dorsad 
as  in  Cossula;  Dyspessa  ulula  Borkh.  has  rudimentary  crochets  in  indefi- 
nite transverse  rows  but  all  the  spiracles  are  in  line. 

Prionoxystus  rohiniae  is  our  most  common  species.  The  larva,  which 
bores  in  locust  and  other  trees,  often  reaches  a  length  of  three  inches. 
P.  macmurtrei,  the  only  other  species,  is  smaller  and  bores  in  a  number  of 
different  trees.  The  crochets  of  the  latter  species  are  circular  in  arrange- 
ment while  those  of  the  former  are  in  a  very  narrow  ellipse. 

Cossus  centerensis  has  a  larval  structure  nearly  identical  with  that 
of  Prionoxystus.  The  two  are  hard  to  distinguish  and  the  character 
given  in  the  table  does  not  hold  for  European  species  of  Cossus.  There 
is  a  Rocky  Mountain  species,  the  larva  of  which  I  have  not  seen. 

Zeuzera  pyrina  has  a  world-wide  distribution.  Like  Cossula  mag- 
nifica, it  is  distinct  from  the  other  forms  and  is  the  only  species  of  the 
genus  found  in  North  America. 

Larvae  of  the  western  genus  Hypopta  and  the  subtropical  Inguro- 
morpha  have  not 'been  seen. 

Family  Pstchtoae 

The  Bagworm  moths  are  a  peculiar  group  which  Dyar  at  one  time 
considered  as  deserving  the  erection  of  a  separate  suborder.  He  seems 
later  to  have  abandoned  this  view,  which  was  based  on  the  fact  that 
alpha  and  beta  are  located  on  the  same  annulet  of  the  abdominal  seg- 
ments instead  of  on  successive  ones.  The  homology  seems  clear  enough 
altho  the  position  of  the  setae  is,  it  is  true,  different  from  that  found  in 
other  larvae.  This  combined  with  the  absolutely  unique  horizontal  pro- 
thoracic  spiracle  shows  that  the  family  is  an  ancient  one.  The  different 
genera  are  remarkably  uniform. 

Head  overarched  by  the  prothorax  above  but  large  and  not  truly 
retractile;  front  and  adfrontals  various;  labrum  notched  to  about  half 
its  depth;  ocelli  normal.  Body  with  primary  setae  only,  these  very 
minute  in  later  stages.  Prothorax  with  all  setae  normal.  Kappa  group 
trisetose,  epsilon  and  rho  distant  from  each  other ;  mesothorax  and  meta- 
thorax  normal  except  that  the  Pi  group  is  bisetose.  Abdomen  with 
alpha,  beta,  and  rho  in  almost  a  straight  line  above  the  spiracle,  but 
alpha  and  beta  close  together  on  segment  9;  kappa  and  eta  adjacent; 
mu  present;  Pi  group  normal.    Prolegs  present  as  usual  on  segments  3, 


79]  LEPIDOPTEROUS    LARVAE  — FRACKER  79 

4,  5,  6,  and  10,  the  crochets  arranged  in  the  same  uniordinal,  lateral 
peuellipse  on  the  anal  as  on  the  ventral  pairs  (Fig,  85).  Spiracles  ellip- 
tical, the  prothoracic  pair  much  larger  than  those  of  the  abdomen  and 
placed  horizontally  (Fig.  69). 

While  the  body  setae  offer  some  characters  of  taxonomic  importance 
in  separating  the  genera,  I  hesitate  to  use  them  on  account  of  their  great 
reduction.  In  many  cases  it  is  impossible  to  find  them  without  a  pro- 
longed search.  This  is  not  true,  however,  of  the  head  setae,  whose  loca- 
tion is  distinct.  The  fact  that  their  position  varies  with  the  different 
genera  is  fortunate,  for  the  coloration  and  general  shape  of  the  body  are 
too  constant  to  aid  in  identification. 

In  the  following  synopsis  the  division  into  Solenobiinae  and  Psy- 
chinae  is  retained  and  some  new  facts  are  added  to  the  characters  Forbes 
used  in  their  separation.  With  one  exception  his  larvae  were  of  differ- 
ent species  from  the  ones  mentioned  below. 

Genera  of  Psychidae : 

a.  Second  adfrontal  seta  much  farther  dorsad  than  frontal  seta,  first 

adfrontal  seta  above  level  of  top  of  front  (Fig.  83)  ;  thoracic  legs 

with  last  two  segments  very  slender;  alpha  of  abdomen  above  level 

of  beta.     (Solenobiinae.)  Solenohia 

aa.  Second  adfrontal  seta  very  close  to  frontal  seta,  first  adfrontal  seta 

below  level  of  top  of  front  (Figs.  76,  79,  82)  ;  thoracic  legs  with 

last  two  segments  stout;  alpha  of  abdomen  below  level  of  beta. 

(Psychinae.) 

b.  Margins  of  adfrontals  meeting  dorsad  at  an  acute  angle,  adfrontals 

scarcely  widened  above  first   adfrontal  seta    (Fig.   76)  ;  larvae 

small,  pale,  not  exceeding  two  centimeters  in  length. 

Eurycittarus 

bb.  Margins  of  adfrontals  meeting  dorsad  at  a  very  obtuse  angle  or 

in  a  horizontal  line;  larvae  three  to  five  centimeters  in  length  in 

last  stage,  usually  dark  in  color. 

c.  Frontal  seta  located  below  line  connecting  second  adfrontal  seta 

with  frontal  puncture   (Fig.  78).  Thyridopteryx 

cc.  Frontal  seta  located  above  line  connecting  second  adfrontal  seta 

with  frontal  puncture  (Fig.  82).  Oiketicus 

The  following  species  were  studied:  Solenohia  walshella,  Eurycit- 
tarus confederata,  Thyridopteryx  ephemeraeformis,  and  Oiketicus  ab- 
botii.  All  are  approximately  unicolorous  except  for  a  tendency  to  lon- 
gitudinal light  and  dark  stripes  on  the  thorax,  especially  on  the  dorsal 
half.  Two  other  species,  Platoeceticus  gloveri  of  Florida  and  Chalia 
rileyi  of  the  "Atlantic  States"  are  found  east  of  the  Rockies  but  they 


80  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [80 

are  rather  rare  and  their  larvae,  so  far  as  I  know,  have  not  been  recog- 
nized. 

Family  Elachistidae 

The  Tineidae  and  Elachistidae  have  long  been  dumping  grounds 
for  all  manner  of  Microlepidoptera.  It  is  within  the  last  five  or  six 
years  (1909)  that  Busck  has  pointed  out  the  necessity  of  dividing  and 
redividing  these  "families".  The  Elachistidae  appear  to  contain  six 
well  defined  groups,  five  in  addition  to  those  related  to  Elachista.  These 
are  now  known  as  Cycnidioidea,  Coleophoridae,  Cosmopterygidae,  Helio- 
dinidae,  and  Scythridinae  of  Yponomeutidae.  Larvae  of  the  true  Ela- 
chistidae and  of  the  superfamily  Cycnidioidea  have  not  been  examined, 
Scythridinae  and  Heliodinidae  are  discussed  in  their  proper  place  in  the 
Yponomeutoidea.  Cosmopterygidae  will  be  found  under  Gelechioidea 
while  Coleophoridae  apparently  do  not  belong  in  any  of  the  superfamilies 
listed  in  this  paper. 

Family  Coleophoridab 

Head  scarcely  depressed;  front  extending  about  two-thirds,  ad- 
frontals  all  the  way  to  the  vertical  triangle;  oceUi  all  close  together, 
seta  vii  closest  to  second  ocellus,  fourth  oceUus  usually  as  close  to  sixth 
as  to  fifth.  Body  cylindrical,  setae  almost  indistinguishable,  apparently 
in  the  normal  mierolepidopterous  arrangement.  Thoracic  legs  about  as 
far  apart  as  the  width  of  the  coxae;  ventral  prolegs  each  bearing  two 
transverse  uniserial  bands  of  uniordinal  crochets,  usually  so  close  to 
ventromeson  that  the  bands  of  the  right  and  left  sides  are  nearly  con- 
tinuous with  each  other;  anal  prolegs  each  with  a  single  transverse  row 
close  to  ventromeson.  Crochets  reduced  in  number  in  some  species, 
either  rudimentary  and  reduced  from  two  to  six  for  each  proleg  as  in 
Coleophora  fletcherella,  or  entirely  wanting  as  in  C.  limospenella.  Spi- 
racles small,  circular,  those  of  the  eighth  abdominal  segment  twice  as 
large  and  slightly  farther  dorsad  than  those  of  other  segments. 

The  following  species  of  Coleophora  were  seen,  all  of  them  having 
transverse  rows  of  crochets  except  as  noted  above:  tUiaefoliella,  atripli- 
civora,  fletcherella,  gaUipeneUa,  ochripeneUa,  limospenella,  and  several 
others  unidentified. 

SUPERFAMILY  GELECHIOIDEA 

This  group  includes  the  most  highly  specialized  of  the  tineoid  series 
of  Microlepidoptera.  Some  of  the  families  are  difficult  to  separate  in 
any  stage,  especially  as  Gelechia  seems  to  be  rather  a  generalized  genus 
from  which  several  others  diverged.    The  characters  are  such  that  the 


81]  LEPIDOPTEROUS    LARVAE  — FR ACKER  81 

interrelations  of  the  families  can  not  be  worked  out  from  them  altho 
there  are  a  sufficient  number  of  differences  to  separate  them  more  or 
less  completely  from  each  other. 

Family  Ethmiidae 

This  family  was  named  and  described  in  1909  by  Busck  to  accom- 
modate the  genus  Ethmia,  hitherto  included  in  Oecophoridae.  The  new 
family  was  based  wholly  on  characters  of  the  adult,  hence  it  is  a  strik- 
ing fact  that  the  larvae  of  Ethmia  are  distinctly  different  from  those 
of  any  of  the  other  genera  usually  associated  with  it.  Unfortunately  the 
larvae  of  but  two  species,  E.  zelleriella  and  E.  longimaculella,  were 
available,  but  their  characters  are  important  enough  to  make  the  follow- 
ing record  of  them  desirable. 

Head  smaller  than  prothorax,  bearing  primary  setae  only;  front 
with  dorsal  half  of  lateral  margins  straight;  adfrontals  not  reaching 
vertical  triangle ;  labrum  moderately  emarginate  at  tip ;  ocelli  six,  the 
fourth,  fifth,  and  sixth  forming  a  triangle  with  an  acute  angle  at  the 
fourth,  the  fourth  farther  from  the  fifth  than  from  the  sixth.  Protho- 
rax with  alpha  slightly  closer  to  dorsomeson  than  beta,  other  setae  in 
usual  positions;  mesothorax  and  metathorax  normal.  Abdomen  with 
alpha  above  level  of  beta,  rho  dorsad  of  spiracle  on  segments  1  to  7, 
eephalad  on  segment  8,  kappa  and  eta  adjacent,  mu  present.  Pi  group 
various,  sigma  present.  Prolegs  short,  with  an  extended  mesoseries  of 
biordinal  crochets.  Spiracles  elliptical,  slightly  larger  on  segment  8 
but  no  higher  on  body. 

In  Ethmia  zelleriella  the  Pi  group  of  the  abdominal  segments  is 
trisetose  as  usual,  while  in  E.  longimaculella  the  number  is  increased  to 
eight  or  ten  setae.  In  neither  species,  however,  is  there  any  increase  of 
setae  on  the  thorax. 

Family  Stenomidae 

Recent  study  has  shown  that  moths  belonging  to  the  genera  Ste- 
noma,  Brachiloma,  and  Ide  do  not  belong  to  the  Australian  family 
Xylorictidae  where  they  were  formerly  placed,  but  constitute  a  separate 
group.  According  to  Busck  the  three  genera  should  be  united  under 
the  name  Stenoma. 

Head  rather  broad  and  depressed,  the  mouth  parts  directed  eepha- 
lad ;  front  extending  less  than  half  way  to  vertex,  and  adfrontals  little 
farther;  labrum  distinctly  but  not  deeply  emarginate;  ocelli  six;  pri- 
mary setae  only.  Body  depressed,  the  spiracles  somewhat  below  the 
middle  of  the  lateral  aspect.  Prothorax  with  rho  near  epsilon  below 
gamma,  and  the  Kappa  group  trisetose;  other  two  thoracic  segments 
with  Pi  group  unisetose.    Abdomen  with  kappa  and  eta  adjacent,  beta 


82  ILUNOIS  BIOLOGICAL  MONOGRAPHS  [82 

farther  laterad  than  alpha  except  on  segment  8  where  they  are  at  about 
the  same  level,  and  segment  9  where  it  is  farther  mesad;  kappa,  eta, 
and  mu  on  segment  9  located  on  the  same  pinaculum.  Thoracic  legs 
adjacent,  prologs  short,  each  bearing  a  complete  circle  of  biordinal  cro- 
chets; anal  prolegs  bearing  a  single  series  of  crochets  on  the  cephalic 
margin. 

Stenoma  humUis  has  a  small  head,  uniform  in  color  and  less  than 
one-third  the  diameter  of  the  body,  while  in  S.  schlaegeri  and  S.  hrillians 
Busck  the  head  is  about  two-thirds  the  width  of  the  body  and  is  trans- 
versely striped,  the  stripe  continuous  in  the  former  but  broken  and 
dotted  in  the  latter. 

Gonioterma  albanum  of  Europe  differs  from  the  American  species 
in  that  the  Kappa  group  on  segments  7  and  8  is  cephalo-ventrad  of  rho 
while  in  Stenoma  it  is  directly  ventrad. 

Family  Hemebophilidae 

Several  important  differences  may  be  noted,  distinguishing  the  lar- 
vae of  this  family  from  those  of  the  Yponomeutidae,  in  which  they  have 
long  been  included.  The  most  important  is  the  close  association  of 
kappa  and  eta  on  the  abdomen  and  the  relative  position  of  alpha  and 
beta  on  the  prothorax. 

Head  longer  than  wide;  front  much  longer  than  wide,  acute  at 
caudal  end,  extending  more  than  half  way  to  vertical  triangle ;  adfront- 
als  narrow;  ocelli  all  close  together.  Prothorax  with  alpha  farther 
laterad  than  beta,  rho  distant  from  epsilon.  Kappa  group  trisetose,  and 
Pi  group  unisetose  as  usual ;  metathorax  similar.  Abdomen  with  spira- 
cles round  or  broadly  elliptical,  beta  farther  laterad  than  alpha  on  all 
segments  except  9,  where  alpha  is  usually  much  farther  from  dorsome- 
son;  kappa  and  eta  adjacent.  Prolegs  long  and  slender,  with  either  a 
complete  circle  or  mesoseries  of  uniordinal  crochets,  often  poorly 
developed. 

Four  of  the  genera  belonging  to  this  family  have  been  examined 
in  the  larval  stage. 

Choreutis  leucohasis.  Crochets  rudimentary,  arranged  in  a  com- 
plete circle ;  Pi  group  on  segments  2,  7,  and  8  trisetose ;  aU  setae  poorly 
developed;  alpha  and  beta  at  about  the  same  level  on  abdominal 
segments. 

AU&nyma  (HemerophUa)  vicarUis.  Crochets  strongly  chitinized; 
setae  well  developed  and  borne  on  distinct  pinacula ;  otherwise  similar 
to  Choreutis. 

Brenthia  pavonaceUa.  Crochets  in  a  complete  circle;  beta  almost 
directly  ventrad  of  alpha  on  abdominal  segments  1  to  8,  caudad  of 
alpha  on  segment  9. 


83]  LEPIDOPTEROUS    LARVAE  — FRACKER  83 

Trichostibas  parvula  Edwards.  Crochets  in  a  mesoseries;  beta 
caudad  of  alpha  on  abdominal  segments  1  to  8,  dorsocaudad  of  alpha  on 
segment  9 ;  Pi  group  unisetose  on  segments  2,  7,  and  8. 

Family  Gelechiidae 

The  enumeration  of  Gelechiidae  in  Dyar's  List  is  considered  as 
very  nearly  correct  and  will  be  followed  more  closely  than  is  possible 
with  most  other  families  of  Microlepidoptera.  Larvae  of  this  family 
will  be  most  often  confused  with  Pyralididae  and  Tortricidae  on  account 
of  similarity  in  size  and  habit.  The  distinctly  trisetose  Kappa  group 
of  the  prothorax  will  differentiate  from  the  former  and  the  distance  of 
setae  beta  on  segment  9  will  distinguish  from  the  latter.  It  seems  un- 
necessary to  enumerate  such  characters  as  the  location  of  all  the  setae, 
for  the  larvae  are  typical  Micros,  any  important  differences  from  the 
usual  plan  (Figs.  39-42)  being  noted  in  the  tables.  It  might  be  men- 
tioned in  addition  that  the  crochets  are  biordinal  except  in  a  few  degen- 
erate cases,  that  the  front  and  adfrontals  are  very  acute  above,  the  ad- 
frontals  often  reaching  the  vertical  triangle,  that  the  spiracles  are  cir- 
cular in  outline,  those  of  segment  8  usually  being  larger  and  higher  on 
the  body,  and  that  the  ocelli  are  almost  never  arranged  as  described 
for  Oecophoridae  (cf.  Figs.  80  and  81). 

The  following  synopsis  of  the  genera  is  incomplete,  owing  partially 
to  lack  of  material,  but  is  an  arrangement  which  can  be  developed  fur- 
ther as  the  larvae  of  more  species  become  known. 

a.  Crochets  wanting  or  reduced  and  rudimentary;  no  proleg  swellings 
present ;  thoracic  legs  small, 
b.  Body  swollen  and  strongly  tapering  at  ends.  Metzneria 

bb.  Body  nearly  cylindrical,  scarcely  tapering.  Sitotroga 

aa.  Crochets  present  and  well  developed. 

b.  Crochets  of  ventral  prolegs  in  a  complete  circ  e,  usually  biordinal; 
those  of  anal  prolegs  in  a  continuous  transvi.-rse  series, 
c.  Prolegs  long  and  slender ;  crochets  few ;  setae  rudimentary ;  head 
retractile.  Nealyda 

cc.  Prolegs  short  and  stout,  crochets  usually  numerous. 

d.  Setae  rho  of  segment  8  cephalad,  rarely  cephalodorsad  of  spi- 
racle; body  always  striped;  setae  large, 
e.  Abdominal   segment  7   with   setae  beta  closer  together  on 
dorsum  than  setae  alpha;  segment  8  with  setae  beta  far- 
ther apart  than  setae  alpha.  Arogalea 
ee.  Segments  7  and  8  both  with  setae  beta  farther  apart  than 
setae  alpha. 


84  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [84 

f.  Triangle  formed  by  the  three  cephaloventral  ocelli  having 
a  right  or  obtuse  angle  at  the  fourth  ocellus,  the  fifth  as 
close  to  the  fourth  as  to  the  sixth;  coloration  consisting 
whoUy  of  transverse  stripes.  Telph^isa 

ff.  Triangle  formed  by  the  three  cephaloventral  ocelli  always 
having  an  acute  angle  at  the  fourth  ocellus,  the  fifth 
about  equidistant  from  the  fourth  and  sixth;  coloration 
almost  always  including  longitudinal  stripes.     Gelechia 

Recurvaria 
dd.  Seta  rho  of  segment  8  dorsad,  rarely  cephalodorsad,  of  spira- 
cle ;  body  caudad  of  prothorax  entirely  pale ;  setae  minute, 
e.  Head  and  prothorax  usually  strongly  chitinized  and  black. 

Phthorimaea 
ee.  Head  and  prothorax  slightly  chitinized  and  pale. 

Gnorimoschema 

bb.  Crochets  of  ventral  prolegs  in  a  pair  of  transverse  bands,  usually 

biordinal,  those  of  anal  prolegs  in  two  groups,  prolegs  short; 

spiracle  of  abdominal  segment  8  very  large.  Ypsolophus 

Anarsia 
Trichotaphe 
Anacampsis 

The  species  of  Gelechia  vary  greatly. 

The  difference  between  Gnorimoschema  and  Phthorimaea,  as  given, 
is  certainly  not  one  of  generic  value  but  may  serve  to  separate  the  two 
species  studied.  It  is  unlikely  that  the  collector  east  of  the  Mississippi 
wiU  find  larvae  belonging  to  other  species.  According  to  Busck  the  two 
genera  should  be  united. 

The  following  species  were  studied,  in  most  cases  two  to  six  individ- 
uals being  seen.  The  variation  is  a  serious  problem  only  in  the  genus 
Grelechia. 

Metzneria  lapeUa 

Sitotroga  cerealella 

Nealyda  hifidella 

Arogalea  (Paralechia)  cristifasciella 

Telphusa  fuscopunctella 

Recurvaria  sp.  ( ?) 

Phthorimaea  operculella 

Gnorimoschema  gallaesolidaginis 

Trichotaphe  serrativatella,  T.  alacella 

Anarsia  lineatella 

Ypsolophus  ligulellus 

Anacampsis  populella,  A.  lagunculariella,  A.  innocuella 


85]  LEPIDOPTEROUS    LARVAE  — FR ACKER  85 

Gelechia  trialbamaculella,  G.  cercerisella,  G.  hibiscella,  G.  unctulella, 
G.  macuUmarginella,  G.  pseudacaciella,  and  G.  serotinella  of 
North  America,  and  G.  atriplicella,  G.  acuminatella,  G.  rhom- 
hella,  and  G.  mulinella  of  Europe. 

Family  Oecophoridae 

This  is  one  of  the  families  formerly  included  in  Gelechiidae  and  the 
larvae  are  so  similar  to  the  latter  that  no  satisfactory  character  has 
been  found  to  distinguish  the  two  groups.  They  seem  to  divide  along 
the  same  lines  on  the  basis  of  the  position  of  rho  on  segment  8  of  the 
abdomen.  In  all  the  species  seen  the  adfrontals  extend  to  the  vertical 
triangle,  the  prolegs  are  short  and  stout  and  bear  a  complete  circle  of 
biordinal  crochets  and  the  prothoracic  shield  is  lightly  chitinized.  The 
fourth  ocellus  is  always  much  closer  to  the  third  than  to  the  sixth,  and 
the  second  is  always  farther  from  the  first  than  from  the  third.  Other- 
wise the  characters  are  the  same  as  in  Gelechiidae. 

Depressaria  is  the  best  known  genus  in  the  family.  As  a  rule  the 
setae  are  located  on  heavily  chitinized  pinacula,  often  elevated  and 
chalaza-like ;  kappa  and  eta  of  the  abdomen  are  borne  on  a  small  pinacu- 
lum  directly  ventrad  of  rho,  eta  being  located  cephalodorsad  of  kappa 
on  the  first  two  or  three  abdominal  segments ;  rho  on  segment  8  is  always 
a  little  above  the  level  of  the  top  of  the  spiracle,  tho  located  farther 
cephalad  on  the  segment.  Depressaria  heracliana  and  Z>.  cinereocostella 
of  America  and  D.  depressella  of  Europe  were  seen. 

Agonopteryx  Hiibner  has  recently  been  separated  from  Depressaria 
altho  the  difference  between  the  two  is  very  slight  in  any  stage.  This 
genus  agrees  with  all  the  characters  given  in  the  preceding  paragraph 
except  that  eta  is  cephaloventrad  of  kappa  on  the  first  two  or  three 
abdominal  segments.  The  species  examined  were  A.  umhraticostella, 
A.  lythrella,  and  A.  posticella,  all  of  North  America. 

Machimia  tentoriferella  is  a  larva  with  indistinct  and  slightly  chit- 
inized setae  and  with  obscure  or  absent  pinacula;  rho  on  segment  8  is 
cephalad  of  the  spiracle  and  at  the  same  level ;  kappa  and  eta  are  below 
the  spiracle  and  located  farther  caudad  than  rho. 

Psilocorsis  quercicella  and  P.  obsoletella,  formerly  included  in 
CryptolecMa,  are  closely  related  to  the  other  two  genera  mentioned  and 
their  characters  indicate  an  intermediate  position.  The  pinacula  are 
distinct,  rho  on  segment  8  is  directly  cephalad  of  the  spiracle  and  kappa 
and  eta  are  on  a  pinaculum  ventrad  of  rho. 

Oecophora  similella,  Dasystoma  salicella,  and  Chimahache  fagella, 
of  Europe,  are  similar  in  all  important  particulars  to  the  American 
forms. 


86  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [86 

Family  Blastobasidae 

The  larvae  of  this  family  are  very  similar  to  the  last  two  discussed 
but  a  few  differences  remain.  Rho,  on  abdominal  segment  8,  is  caudo- 
dorsad  of  the  spiracle,  while  kappa  is  cephaloventrad,  an  arrangement 
found  in  no  other  larvae.  The  prolegs  are  short  and  bear  a  complete 
series  of  uniordinal  crochets,  which  are,  however,  sometimes  irregular. 
Only  primary  setae  are  present  on  the  body.  Ocelli  indefinite  in  speci- 
mens examined. 

The  species  seen  were :  Valentinia  glandulella  Eiley  and  Holcocera 
gigantella  Ch.  of  North  America  and  Endrosis  lacteella  of  Europe. 

Family  Cosmopterygidae 

Head  more  or  less  depressed,  very  much  so  in  Cosmopteryx,  small, 
retractile  within  prothorax;  adfrontals  not  quite  reaching  vertical  tri- 
angle; ocelli  all  close  together,  seta  vii  closest  to  second  ocellus,  fourth 
ocellus  usually  as  close  to  sixth  as  to  fifth.  Setae  of  body  small;  abdo- 
men with  kappa  and  eta  adjacent ;  setae  beta  of  segment  9  much  farther 
apart  than  each  is  from  alpha  of  that  side,  beta,  alpha,  and  rho  in  a 
transverse  line.  Thoracic  legs  with  coxae  twice  as  far  apart  as  wide; 
prolegs  far  apart,  each  bearing  a  complete  circle  of  uniordinal  (Stilho- 
sis)  or  biordinal  crochets. 

The  following  species  were  examined; 

Cosmopteryx  gemmiferella,  C.  clandestinella, 

Limnoecia  phragmitiella, 

Homaledra  sohalella,  H.  heptathalama,  and 

Stilbosis  tesquella,  of  America,  and 

Cosmopteryx  scribalella, 

Heydenia  fulvigutella,  and 

Laverna  phragmitella  of  Europe. 

SUPERFAMILY   PYRALIDOIDEA 

Scarcely  half  a  dozen  characters  are  common  to  all  the  larvae 
within  this  superfamily.  The  deciding  factors  are  the  presence  of  a 
bisetose  Kappa  group  on  the  prothorax  and  the  close  association  of  kappa 
and  eta  on  the  abdomen.  Some  of  the  Pterophoridae  have  these  points 
obscured  by  secondary  and  tufted  setae,  and  such  incidental  structures 
as  the  circular  spiracles  and  the  long  slender  prolegs  must  be  used  in 
determination.     (Figs.  47,  48,  61.) 

Unless  care  is  taken  in  observing  the  number  of  setae  on  the  pro- 
legs,  Lacosoma  will  trace  to  this  superfamily.  It  is  distinguished  from 
Pyralidoidea  by  the  Pi  group  which  consists  of  from  four  to  eight  setae. 


87]  LEPIDOPTEROUS    LARVAE  — FR ACKER  87 

Family  Pyralididae 

The  superfamily  character  of  a  bisetose  Kappa  group  on  the  pro- 
thorax,  combined  with  the  presence  of  short  prolegs  bearing  either  a 
pair  of  transverse  bands  or  a  more  or  less  complete  circle  of  biordinal 
crochets,  limits  the  family.  In  some  specimens  of  Galleria  mellonella 
the  crochets  seem  to  be  uniordinal  but  no  individuals  have  been  seen 
in  which  that  was  true  of  all  the  prolegs. 

The  family  includes  four  main  divisions  typified  by  the  following 
four  subfamilies:  Chrysauginae,  Galleriinae,  Phycitinae,  and  Pyraus- 
tinae.  The  species  of  the  first  two  are  few  in  number  while  each  of  the 
others  is  very  large  in  addition  to  being  associated  with  several  smaller 
subfamilies.  The  structural  basis  of  these  divisions  is  shown  by  the 
following  synopsis: 

a.  Crochets  uniordinal,  arranged  in  two  transverse  bands;  front  extend- 
ing nearly  and  adfrontals  entirely  to  vertical  triangle. 

Chrysauginae 
aa.  Crochets  arranged  in  a  pseudocircle  or  penellipse,  very  rarely  uni- 
ordinal. 
b.  Pi  group  on  mesothorax  and  metathorax  bisetose ;  crochets  some- 
times uniordinal  (Fig.  50).  Galleriinae 
bb.  Pi  group  on  mesothorax  and  metathorax  unisetose;  crochets  al- 
ways biordinal  or  triordinal. 
c.  Kappa  and  mu  present  on  segment  9,  usually  associated  with  eta 
on  the  same  pinaculum  (Fig.  46)  ;  crochets  arranged  in  a  com- 
plete circle.                                                                Epipaschiinae 

Pyralidinae 
Phycitinae 
cc.  Kappa  and  mu  absent  or  extremely  minute  on  segment  9,  eta 
well  developed,  not  associated  with  other  setae  (Fig.  49). 
d.  Crochets  arranged  in  a  penellipse. 

e.  Crochets  biordinal.  (In  part)  Crambinae 

ee.  Crochets  triordinal  (Fig.  98).  Pyraustinae 

dd.  Crochets  arranged  in  a  complete  circle. 

e.  Crochets  triordinal.  (In  part)  Crambinae 

ee.  Crochets  biordinal.     (See  also  subfamily  descriptions.) 

Nymphulinae 
Scopariinae 

Chrysauginae.  This  subfamily  must  have  been  separated  from 
other  pyralids  at  a  rather  remote  period  in  their  history,  for  intermedi- 
ate stages  are  lost  and  the  differences,  especially  in  the  crochets,  are 
striking.    The  chaetotaxy  is  as  in  the  other  subfamilies  but  it  may  be 


88  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [88 

noted  that  the  Pi  group  on  the  mesothorax  and  metathorax  is  unisetose, 
that  alpha  on  segment  9  is  about  as  far  from  rho  as  from  beta,  and  that 
kappa,  eta,  and  mu  are  present  and  subequal  in  size,  but  not  closely- 
associated  with  each  other.  The  species  examined  was  Clydonopteron 
(Salohrana)  tecomae. 

Galleriinae.  Aside  from  their  peculiar  habits  as  pests  of  beehives, 
these  larvae  are  easy  to  recognize  by  distinctive  structures  as  well.  The 
Pi  group  on  the  last  two  thoracic  segments  is  bisetose ;  the  two  setae  of 
the  Kappa  group  on  the  prothorax  as  well  as  the  abdomen  are  nearly 
in  a  horizontal  line  instead  of  a  vertical  one  as  usual;  the  crochets  are 
either  biordinal  or  uniordinal,  never  triordinal,  and  are  arranged  in  a 
complete  circle;  alpha,  beta,  and  rho  on  segment  9  form  an  equilateral 
triangle,  rho  being  directly  ventrad  of  beta. 

Two  species  were  examined.  In  Galleria  mellonella  (^cereana) 
the  body  is  thickened  in  the  middle  and  tapering  towards  both  ends  and 
the  coxae  of  the  metathoracic  legs  are  twice  as  far  apart  as  wide.  In 
Achroia  grisella  the  body  is  cylindrical  and  the  thoracic  legs  are  close 
together. 

Epipaschiinae.  This  small  group  is  a  closely  circumscribed  one 
with  characters  which  associate  it  with  Phycitinae.  A  few  of  the  latter 
show  nearly  all  the  peculiarities  of  this  subfamily,  so  Epipaschiinae  are 
introduced  into  the  table  for  the  separation  of  the  genera  of  Phycitinae 
instead  of  being  separated  from  them  in  the  synopsis  of  the  subfamilies. 
The  crochets  are  triordinal,  the  longest  about  four  times  the  length  of 
the  shortest.    Other  characters  are  given  in  the  synopsis  of  Phycitinae. 

The  following  species  were  examined:  Epipaschia  superatalis,  E. 
zelleri,  Jocara  perseella  B.  &  McD,,  Tetralopha  mUitella,  T.  floridella, 
and  T.  rohustella. 

Pyralidinae.  While  the  structure  of  the  three  species  of  Pyralidi- 
nae*  examined  is  quite  constant,  it  is  almost  impossible  to  find  a  charac- 
ter which  will  distinguish  them  from  Phycitinae  as  a  whole.  They  will 
be  found  in  the  table  of  genera  of  the  latter  group.  In  Pyralis  farinalis 
the  crochets  are  biordinal,  the  shorter  ones  about  one-fourth  the  length 
of  the  others  (Fig.  101),  but  those  of  Omphalocera  dentosa  and  0. 
cariosa  are  as  in  the  two  related  subfamilies.  In  all  three  species  beta 
is  clearly  in  the  caudad  row  of  the  setae  on  the  prothoracic  shield  and 
is  scarcely  farther  cephalad  than  delta;  the  third  and  fourth  ocelli  are 
close  together  and  the  fourth  out  of  line;  the  front  extends  about  half 
way  to  vertical  triangle  and  the  adfrontals  about  two-thirds;  and  the 
head  is  about  as  broad  as  long.  In  color  Pyralis  is  pale  while  the  species 
of  Omphalocera  are  dark  with  white  pinacula. 


*The  larva  of  Hypsopygia  costalis,  examined  since  writing  the  above,  agrees 
with  Pyralis  with  respect  to  the  prolegs,  and  will  trace  near  to  this  genus  in  the  key. 


89]  LEPIDOPTEROUS    LARVAE  — FR ACKER  89 

Phycitinae.  This  group  aud  Pyraustinae  are  the  two  large  sub- 
families of  Pyralididae  and  many  of  the  larvae  of  both  of  them  are  of 
economic  importance.  They  represent  two  diverging  lines  of  evolution, 
the  one  characterized  by  a  complete  circle  of  crochets  on  the  prolegs  and 
the  presence  of  kappa  and  mu  on  segment  9,  the  other  losing  the  lateral 
crochets  of  the  prolegs  as  well  as  kappa  and  mu  on  segment  9.  Asso- 
ciated with  Phycitinae  in  the  former  division  are  the  two  subfamilies 
just  discussed,  and  all  three  are  included  together  in  a  single  synopsis 
of  the  genera,  those  belonging  to  Pyralidinae  being  marked  with  an 
asterisk  (*). 

Genera  of  Phycitinae,  Pyralinae,  and  Epipaschiinae : 

a.  Prothorax  with  delta  twice  as  far  caudad  of  beta  as  beta  is  of  alpha, 
alpha  and  beta  usually  closely  associated  (Fig.  47). 
b.  Head  longer  than  broad ;  body  unicolorous,  dark.        Thyridopyralis 
bb.  Head  broader  than  long, 
c.  Boundaries  of  adfrontals  meeting  epicranial  suture  at  a  point 
nearly  twice  as  far  from  vertical  triangle  as  f i'om  front ;  colora- 
tion in  longitudinal  stripes.  Meroptera 
cc.  Boundaries  of  adfrontals  meeting  epicranial  suture  at  a  point 
half  way  between  vertical  triangle  and  front, 
d.  Kappa  nearly  directly  caudad  of  eta  on  first  abdominal  seg- 
ment; fourth  ocellus  about  as  close  to  sixth  as  to  third. 

Euzophera 

dd.  Kappa  directly  dorsad  of  eta  on  first  abdominal  segment; 

fourth  ocellus  farther  from  sixth  than  from  third. 

e.  Pinacula  of  all  setae  heavily  chitinized;  body  widened  at 

middle.  Melitara 

ee.  Pinacula  of  all  setae  slightly  chitinized;  body  cylindrical. 

Salehria 
aa.  Prothorax  with  delta  much  less  than  twice  as  far  caudad  of  beta  as 
beta  is  of  alpha,  beta  and  delta  often  closely  associated  (Fig.  43). 
b.  Beta  of  prothorax  nearly  directly  dorsad  of  delta;  head  and  body 
pale  (Fig.  43).  Psorosina 

bb.  Beta  of  prothorax  located  much  farther  cephalad  than  delta, 
c.  Boundaries  of  adfrontals  reaching  vertical  triangle. 

d.  Vertical  triangle  nearly  as  large  as  front;  prothoracic  shield 

black.  Elasmopalpus 

dd.  Vertical  triangle    normal,  small;    prothoracic    shield    pale; 

pinacula  slightly  chitinized.  Hulstea 

cc.  Boundaries  of  adfrontals  not  reaching  vertical  triangle. 

d.  Kappa   of   first   abdominal   segment   directly   dorsad   of   eta; 
boundaries  of  adfrontals  meeting  in  an  acute  point. 


90  ILLINOIS   BIOLOGICAL   MONOGRAPHS  [90 

e.  Three  ventral  ocelli  not    forming    an    equilateral    triangle, 
angle  at  sixth  ocellus  right  or  obtuse  (Fig.  71). 
f.  Front  extending  about  two-thirds  of  the  distance  to  ver- 
tical triangle ;  adfrontals  meeting  epicranial  suture  about 
half  way  between  front  and  vertical  triangle.  Plodia 

ff.  Front  extending  about  half  way  to  vertical  triangle, 
g.  Boundaries  of  adfrontals  meeting  epicranial  suture  about 
half  way  between  front  and  vertical  triangle ;  crochets 
biordinal,   the   longer    four   times  the   length   of   the 
shorter  (Fig.  101).  Py rails* 

gg.  Boundaries  of  adfrontals  meeting  epicranial  suture 
at  a  point  about  twice  as  far  from  the  vertical  triangle 
as  from  front;  crochets  triordinal.  Ephestia 

V it  Ilia 
ee.  Three  ventral  ocelli  forming  an  equilateral  triangle,  acute 
angle  at  each  ocellus  (Fig.  70)  ;  front  reaching  about  half 
way  to  vertical  triangle, 
f .  Head  rugose ;  body  dark.  Acrohasis 

ff.  Head  smooth.  Mineola  (a) 

dd.  Kappa  of  first  abdominal  segment  directly  caudad  of  eta  or 
nearly    so;    front    extending    about    half    way    to    vertical 
triangle, 
e.  Second  ocellus  not  closer  to  third  than  to  first;  body  not 
striped, 
f.  Lateral  margins  of  adfrontals  convex  dorsad,  meeting  in 
an  obtuse  angle ;  body  dark,  not  spotted.  Tacoma 

ff.  Lateral  margins  of  adfrontals  nearly  straight,  meeting  in 
an  acute  angle. 
g.  Body  and  pinacula  pale.  Canarsia 

Mineola  (b) 
gg.  Body  black  with  white  pinacula.  Omphalocera* 

ee.  Second  ocellus  much  closer  to  third  than  to  first;  first  ocel- 
lus larger  than  others;  lateral  margins  of  front  very  con- 
vex; body  striped,  usually  longitudinally.  (See  subfam- 
ily.) Epipaschiinae 

The  following  species  of  Phycitinae  were  examined: 

Thyridopyralis  gallaerandalis  (heretofore  included  in  Thyrididae) 
Meroptera  pravella 

Euzophera  ostricolorella  Melitara  prodenialis 

Salehria  contatella  Psorosina  (Canarsia)  hammondi 

Elasmopalpus  lignosellus  Hulstea  undulatella 

Plodia  interpunctella  Ephestia  kuehniella,  E.  cautella 


91]  LEPIDOPTEROUS    LARVAE— FRACKER  91 

Vitula  edmandsii  Acrobasis  hetulella 
Mineola  indiginella  (a)  A.  comptoniella 

M.  amplexella  (b)  A.  stigmella  Dyar 

Tacoma  nyssaecolella  Canarsia  ulmiarrosorella 

Cramhinae.  The  larvae  of  many  species  of  Crambus  are  of  economic 
importance  and  should  be  familiar  to  entomologists.  They  can  not 
readily  be  differentiated  from  each  other,  but  can  be  distinguished  from 
other  groups.  Any  larva  with  a  complete  circle  of  triordinal  crochets, 
with  but  two  setae  in  front  of  the  prothoracic  spiracle,  with  a  single 
seta  on  segment  9  caudad  of  the  spiracle  on  segment  8  and  with  but  one 
seta  at  the  base  of  each  mesothoracic  leg,  is  a  crambid.  In  addition 
there  are  a  few  species  which  closely  resemble  Pyraustinae.  Crambus 
trisectus,  Chilo  prejadellus,  and  Dicymolomia  jidianalis,  together  with 
a  large  number  of  unidentified  species  of  Crambus,  were  examined. 

Pyraustinae.  The  penellipse  of  crochets  which  characterizes  this 
subfamily  varies  in  extent  from  a  semicircle  to  an  almost  complete 
ellipse.  Other  subfamilies  are  entirely  distinct,  except  a  few  Crambinae, 
most  of  which  have  biordinal  crochets. 

Genera  of  Pyraustinae : 

a.  Front  extending  three-fourths,  adfrontals  nearly  or  all  the  way,  to 
the  vertical  triangle, 
b.  Kappa  on  eighth  abdominal  segment  located  directly  dorsad  of  eta ; 
first  ocellus  much  larger  than  others.  Hellula 

bb.  Kappa  on  eighth  abdominal  segment  located  caudodorsad  of  eta; 
first  ocellus  not  much  larger  than  others, 
e.  Adfrontals  not  strongly   widened  above,   their  lateral  margins 
rather  regularly  convergent;  head  normal  in  size, 
d.  Head  not  bilobed  above,  except  slightly  in  some  species, 
e.  Spiracles  elliptical  in  outline,  heavily  chitinized,  normal  in 
size ;  body  with  black  pinacula  and  sometimes  black  stripes. 

Loxostege 
ee.  Spiracles  circular  in  outline,  slightly  chitinized,  very  small; 
body  decorated  with  transverse  red  stripes.  Eustixia 

dd.  Head  conspicuously  bilobed  above,  with  the  epicranial  suture 
forming  a  deep  groove  between  the  lobes;  head  black,  body 
marked  with  conspicuous  black  and  white  spots.        Tholeria 
cc.  Adfrontals  strongly  widened  above  so  that  their  lateral  boun- 
daries appear  to  be  parallel  to  each  other  for  the  ventral  three- 
fourths  of  their  length ;  head  very  small.  Cybalomia 


92  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [92 

aa.  Front  extending  less  than  two-thirds  of  the  distance  to  vertical  tri- 
angle* ;  adfrontals  not  reaching  vertical  triangle ;  ocelli  subequal  in 
size. 
b.  Eho  on  eighth  abdominal  segment  directly  dorsad  of  spiracle. 

Hymenia 
bb.  Eho  on  eighth  abdominal  segment  cephalodorsad  of  top  of  spiracle, 
c.  Second  ocellus  about  half  way  between  first  and  third;  seta  vii 
usually  closest  to  second  ocellus;  penellipse  more  than  a  semi- 
circle, 
d.  Front  with  sides  straight  or  concave. 

e.  Alpha  and  rho  on  ninth  abdominal  segment  in  a  horizontal 
line;  head  not  depressed;  labrum  with  a  rounded  emargi- 
nation.  Pachyzancla 

ee.  Alpha  and  rho  on  ninth  abdominal  segment  not  in  a  hori- 
zontal line,  except  in  some  species  in  which  the  labrum  has 
an  acute  notch, 
f .  Head  very  much  depressed ;  labrum  with  an  acute  notch. 

Desmia 
ff.  Head  not  depressed;  labrum  usually  not  with  an  acute 
notch. 
g.  Pinacula  heavily  chitinized,  black.  Pyrausta 

gg.  Pinacula  slightly  chitinized,  pale.  Phlyctaenia 

dd.  Front  with  sides  rather  convex  throughout  their  entire  length ; 
seta  vii  closest  to  third  ocellus, 
e.  Adfrontals  conspicuously  widened  above  the  front.     Sylepta 
ee.  Adfrontals  not  widened  above  the  front.  Terastia 

cc.  Second  ocellus  much  closer  to  first  than  to  third ;  seta  vii  closest 
to  third  ocellus;  penellipse  less  than  a  semicircle, 
d.  Setae  alpha  of  first  abdominal  segment  more  than  twice  as  far 
apart  as  each  is  from  beta;  body  bearing  subdorsal  longitu- 
dinal stripes  or  dotted  areas;    subdorsal    pinacula    heavily 
chitinized.  Evergestis 

dd.  Setae  alpha  of  first  abdominal  segment  not  more  than  one 
and  a  half  times  as  far  apart  as  each  is  from  beta, 
e.  Alpha  directly  dorsad  of  rho  on  eighth  abdominal  segment, 
f.  Labrum    very    broad    and    short,  shallowly    but    acutely 
emarginate ;  head  spotted.  Dichogama 

ff.  Labrum  normal,  with  a  rounded  emargination ;  head  uni- 
colorous. 
g.  Thoracic  legs  and  abdominal  prolegs  short  and  often 
stout. 


*Except  sometimes  in  Evergestis  which  may  fall  in  "a' 


93]  LEPIDOPTEROUS    LARVAE  — FRACKER  93 

h.  Head  compressed,  retractile,  one  and  a  half  times  as 

long  as  prothorax.  Diaphania 

hh.  Head    not    compressed,   not    noticeably    retractile, 

smaller  than  prothorax.  Asciodes 

gg.  Thoracic  legs  and  abdominal  prolegs  long  and  slender ; 

head  not  compressed,  not  greater  than  prothorax  in 

height. 

h.  Head  higher  than  broad;  body  pale.        Pantographa 

hh.  Head  broader  than  high;  body  marked  with  black 

spots.  Epicorsia 

ee.  Alpha  located  much  farther  cephalad  than  rho  on  eighth 

abdominal  segment.  Paradosis 

The  following  species  were  examined : 

Hellula  undalis  Loxostege  sticticalis 
Phlyctaenia  extricalis  L.  mancalis 

P.  tertialis  L.  maclurae 

Eustixia  pupula  Tholeria  reversalis 

Cybalomia  belialis  Hymenia  perspectalis 

Pachyzancla  hipunctalis  Desmia  funeralis 

Pyrausta  penitalis  Sylepta  fluctuosalis 

P.  cingulata  Terastia  meticulosalis 

P.  thestealis  Evergestis  dyaralis 
Dichogama  redtenhacheri  E.  rimosalis 

Diaphania  nitidalis  Asciodes  gordialis 

D.  quadristigmalis  Pantographa  limata 

D.  sihillalis  Epicorsia  mellinalis 
Paradosis  flegia 

Nymphulinae.  All  the  aquatic  Pyralidoidea  of  America  are  in- 
cluded in  this  subfamily.  The  resulting  structural  modifications  cause 
some  difficulty  in  studying  the  chaetotaxy  of  the  larvae.  The  few  species 
with  tracheal  gills  are  easily  identified,  for  no  other  insects  possess  both 
gills  and  prolegs  with  crochets. 

Alpha  is  located  near  rho  but  the  relative  position  of  the  two  varies 
in  different  genera.  Elophila  and  Nymphula  differ  from  Scopariinae 
and  Crambinae  in  the  fact  that  the  setae  beta  on  segment  9  are  three 
times  as  far  apart  as  each  is  from  alpha  of  that  side,  alpha  being  nearly 
in  a  direct  line  between  beta  and  rho  and  close  to  each  of  them.  On  the 
other  hand  Geschna  has  the  setae  beta  located  near  the  dorsomeson  as 
usual  but  differs  from  other  Pyralidoidea  in  the  position  of  alpha,  which 
is  directly  cephalad  of  and  close  to  rho.  The  kappa  group  on  segment  9 
is  rather  difficult  to  locate  in  this  subfamily.  The  species  examined 
were : 


94  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [94 

Nymphula  ohscuraliSy  N.  ohliteralis, 
Geschna  (Nymphula)  cannalis 
Elophila  lemnata 

Scopariinae.  No  American  species  of  this  subfamily  have  been  seen. 
Scoparia  crataegella  has  kappa  and  eta  of  the  prothorax  forming  a  ver- 
tical line ;  kappa  and  eta  of  the  abdomen  forming  a  horizontal  line ; 
alpha  of  segment  9  close  to  and  cephalodorsad  of  rho;  beta  of  segment 
9  close  to  dorsomeson  and  located  farther  caudad  than  alpha  and  rho; 
kappa  and  mu  absent  from  this  segment;  crochets  biordinal,  not  tri- 
ordinal,  in  a  complete  circle.    Otherwise  similar  to  Crambinae. 

Family  Orneodidae 

Head  mainly  horizontal  in  position,  smaller  than  prothorax,  smooth ; 
front  extending  about  two-thirds  of  the  distance  to  the  vertical  triangle ; 
adfrontals  indistinct;  first  five  ocelli  arranged  in  an  arc,  with  the  sixth 
behind  the  fifth;  no  secondary  setae  present.  Body  pale,  bearing  pri- 
mary setae  only;  shape  cylindrical;  intersegmental  incisions  moderate. 
Prothorax  with  alpha,  gamma  and  epsilon  in  a  transverse  row,  beta  and 
delta  normal  and  rho  behind  and  slightly  below  level  of  epsilon ;  Kappa 
group  bisetose;  Pi  group  bisetose;  mesothorax  with  kappa  closer  to  eta 
than  to  theta,  otherwise  normal.  Abdomen  with  alpha  above  level  of 
beta,  rho  dorsad  of  spiracle,  kappa  and  eta  adjacent,  mu  present;  Pi 
group  consisting  of  one  seta  on  segments  1,  7,  and  8  and  of  three  setae 
on  segments  2  to  6  inclusive ;  segments  9  and  10  damaged  in  material 
examined.  Spiracles  circular,  slightly  larger  on  prothorax  than  on 
other  segments,  located  farther  dorsad  on  segment  8  than  on  segments 
1  to  7.  Prolegs  short,  present  on  segments  3,  4,  5,  and  6,  bearing  a 
complete  circle  of  uniordinal  crochets. 

The  family  contains  but  one  species,  Orneodes  hexadactyla.  It  will 
be  seen  from  the  description  that  the  structure  is  essentially  that  of  a 
pyralid,  being  distinguished  from  all  other  micros,  except  some  Pter- 
ophoridae,  by  the  bisetose  Kappa  group  of  the  prothorax.  Galleria 
is  the  only  genus  of  Pyralididae  which  ever  has  uniordinal  crochets  and 
in  it  the  body  is  fusiform,  the  size  large,  and  the  Pi  group  on  the 
mesothorax  is  bisetose. 

Family  Pterophoridae 

Variations  in  the  characters  of  the  Plume-moth  larvae  are  so  nu- 
merous that  some  difficulty  may  be  met  with  in  placing  some  of  the 
species.  In  practice,  however,  one  soon  learns  to  know  the  long,  stem- 
like prolegs,  regardless  of  the  number  of  setae  or  crochets.  (See  Fig.  61.) 
No   other   caterpillars   possessing  verrucae   and    secondary   setae   have 


95]  LEPIDOPTEROUS    LARVAE  — FR ACKER  95 

prolegs  of  this  shape,  altho  a  few  lower  micros  with  primary  setae  show 
similar  structures.  All  of  the  latter,  however,  have  a  trisetose  Kappa 
group  on  the  prothorax  while  that  of  the  Pterophoridae  is  bisetose  as 
in  other  Pyralidoidea.  The  species  examined  were  Pterophorus  elUottii, 
Oxyptilus  periscelidactylus,  Platyptilia  cosmodactyla  of  America,  and 
Pterophorus  microdactylus  and  Platyptilia  rhododactylus  of  Europe. 
In  all  of  these  verrucae  are  developed,  except  in  Pterophorus  micro- 
dactylus where  the  setae  are  as  in  Pyralididae. 

SUPERFAMILY  ZYGAENOIDEA 

We  begin  the  discussion  of  this  superfamily  with  forms  which  have 
reached  the  point  of  the  appearance  of  well  developed  verrucae  and 
mesoserial  crochets.  The  verrucae  later  become  more  strongly  modified 
and  the  crochets  peculiarly  specialized.  Another  step  and  the  crochets 
are  wholly  lost,  while  the  armature  includes  forms  of  scoli  found  in  no 
other  larvae.  The  end  of  the  process  is  seen  in  such  a  slug  caterpillar 
as  Prolimacodes,  with  the  head  minute  and  completely  retracted,  and 
the  body  smooth  and  almost  spherical,  bearing  no  processes  of  any  kind 
except  three  pairs  of  minute  thoracic  legs. 

No  larvae  of  the  families  Chalcosidae  and  Dalceridae  have  been 
seen. 

Family  Pyromorphidae 

Pyromorphid  larvae  form  one  of  the  earliest  steps  in  the  evolution 
of  a  typical  Micro  into  a  slug  caterpillar.  The  Pterophoridae  include  the 
most  plausible  connecting  links  to  the  generalized  types.  The  following 
characters  show  the  close  relation  to  Megalopygidae : 

Head  small,  retractile,  caudal  half  slightly  chitinized;  labrum  with 
a  small  emargination ;  ocelli  all  similar  in  size,  the  fifth  not  set  as  far 
caudad  of  the  fourth  as  in  most  caterpillars ;  primary  setae  only.  Body 
cylindrical,  with  large  flat  verrucae.  Prothorax  with  numerous  setae 
on  cervical  shield,  verruca  of  the  Kappa  group  large ;  mesothorax  and 
metathorax  each  with  the  verrucae  of  the  Kappa  group  and  of  the  Pi 
group  forming  single  verrucae  and  with  three  verrucae  dorsad  of  them 
on  each  side.  Abdomen  (Fig.  59)  with  verruca  alpha  fused  with  beta, 
and  rho  and  the  verruca  of  the  Kappa  group  well  developed ;  mu  pres- 
ent; Pi  group  consisting  of  one  or  two  verrucae.  Prolegs  present  on 
segments  3,  4,  5,  6,  and  10,  each  with  crochets  in  a  uniordinal  mesoseries. 

Triprocris  is  a  western  genus  ranging  from  Mexico  to  Colorado 
and  including  eight  species.  T.  smithsonianus,  the  one  examined,  has  a 
large  subventral  eversible  gland  or  fleshy  protuberance  on  the  prothorax 
associated  with  Pi,  and  two  verrucae,  the  smaller  cephalad  of  the  larger, 
present  between  the  proleg  and  the  verruca  of  the  Kappa  group  on 


96  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [96 

abdominal  segments  2  to  6;  there  is  also  a  similar  pair  of  verrueae  on 
segment  7  but  none  on  8,    The  dorsomeson  is  marked  by  a  dark  line. 

Harrisina  and  Acoloithus  have  the  prothoracic  protuberance  but 
there  is  only  one  verruca  between  that  of  the  Kappa  group  and  the 
proleg  on  segments  2  to  6  and  none  on  7  or  8,  Harrisina  americana  is 
rather  common  in  the  eastern  states,  feeding  on  grape  and  Virginia 
Creeper.  The  larva  is  pale  except  for  the  dark  reddish  verrueae. 
H.  metallica  of  Texas  and  Arizona  has  a  broad  dark  red  lateral  line 
running  just  above  the  spiracle,  and  transverse  intersegmental  stripes. 
The  otherwise  pale  body  of  H.  brillians,  from  the  same  region,  is  gaily 
decked  with  two  broad  reddish  transverse  stripes,  the  cephalic  covering 
parts  of  the  last  thoracic  and  first  two  abdominal  segments  and  the 
caudal  extending  from  the  verrueae  of  the  sixth  abdominal  segment 
to  those  of  the  seventh.  In  addition  the  prothorax,  mesothorax,  and 
fourth  and  eighth  abdominal  segments  bear  narrow  transverse  vittae. 

Acoloithus  falsarius  is  pale,  but  obscurely  dotted  above.  Other 
species  of  Acoloithus  and  Harrisina  are  very  similar  in  the  larval  stage. 
The  adults  in  this  division  of  the  family  will  have  to  be  studied  more 
carefully  before  the  larvae  can  be  correctly  placed.  Apparently  some 
of  the  species  have  dimorphic  larvae. 

The  larva  of  Pyromorpha  dimidiata  is  dull,  dark-colored.  The 
prothorax  does  not  bear  a  subventral  protuberance;  the  verruca  mu  is 
present  on  the  first  seven  abdominal  segments  but  is  not  associated  with 
a  second  verruca  as  in  Triprocris. 

Family  Epepyropidae. 

The  two  species  of  this  family,  one  Asiatic,  Epipyrops  anomala, 
and  one  American,  E.  harieriana,  are  anomalous  caterpillars  with  a 
parasitic  habit.  The  body  is  in  the  form  of  a  depressed  hemisphere, 
the  head  retractile  within  the  first  segments.  Both  thoracic  and  ab- 
dominal legs  are  present,  the  claws  of  the  former  being  peculiar  in 
that  they  bear  a  long  tooth  at  the  base.  The  crochets  are  in  a  complete 
circle  and,  altho  uniordinal,  are  slightly  irregular  in  position  and  length, 
their  form  being  degenerate.  Secondary  setae  are  sparsely  scattered  over 
the  entire  body.  The  small  head,  stout  body,  and  secondary  setae 
indicate  an  affinity  with  the  Zygaenoidea  but  reduction  has  taken  a 
different  direction  than  in  Cochlidiidae.  There  is  no  sign  of  verrueae 
and  the  crochets  are  in  a  complete  circle,  an  arrangement  lost  even 
in  the  Pyromorphidae. 

Family  Megalopygidae. 

This  family  forms  one  of  the  important  links  in  the  Zygaenoidea, 
standing  between  the  Zygaenidae  themselves  and  the  Cochlidiidae.    Its 


97]  LEPIDOPTEROUS    LARVAE  — FRACKER  97 

members  are  particularly  interesting  as  transition  forms  and  their 
structure  is  the  clue  to  the  peculiarities  of  the  slug  caterpillars. 

Head  and  cephalic  part  of  prothorax  retractile ;  head  very  small, 
slightly  chitinized  caudad  of  the  fork  of  the  epicranial  suture;  epicra- 
nium  marked  by  a  transverse  line  between  apical  and  occipital  areas, 
the  former  more  heavily  chitinized ;  labrum  with  a  small  mesal  emargin- 
ation;  fourth  and  fifth  ocelli  much  larger  than  others,  sixth  ocellus  at 
a  distance  from  first  five;  head  setae  sparse  and  slender. 

Body  thickened  in  the  middle,  small  at  the  ends,  fusiform ;  verrucae 
large  but  flat.  Prothorax  with  one  large  verruca  dorsad  of  spiracle,  one 
small  one  (Kappa)  in  front  of  it,  and  two  (Pi)  at  base  of  leg;  mesothorax 
with  three  verrucae.  Beta  group,  rho,  and  epsilon,  above  that  of  the 
Kappa  group,  Beta  the  largest;  two  verrucae  forming  Pi  group  at 
base  of  leg ;  metathorax  with  only  two  verrucae  above  that  of  the  Kappa 
group,  epsilon  and  rho  being  fused;  otherwise  similar  to  mesothorax. 
Abdomen  with  verrucae  alpha  and  beta  coalesced,  kappa  and  eta 
coalesced ;  Pi  group  consisting  of  one  verruca  on  segment  1  and  of  three 
around  the  base  of  each  of  the  six  pairs  of  ventral  prolegs.  Spiracles 
all  circular,  those  of  prothorax  largest.  Prolegs  present  on  segments 
2  to  7  and  10,  those  on  3,  4,  5,  6  bearing  uniordinal  crochets  in  two 
groups,  cephalic  group  the  smaller;  these  two  groups  form  an  angulated 
mesoseries  in  most  cases  but  in  one  genus  they  are  distinctly  separated. 

Carama  creiata.  Fifth  ocellus  as  far  from  fourth  as  from  first; 
two  groups  of  crochets  distinctly  separated ;  verrucae  each  consisting  of 
a  thick  group  of  short  stiff  setae  and  a  few  long  slender  ones. 

Lagoa  crispata  has  the  fifth  ocellus  dose  to  the  fourth,  the  two 
groups  of  crochets  contiguous  and  the  verrucae  each  consisting  of  a  few 
stiff  setae  and  a  great  many  slender  ones.  All  the  setae  are  subequal 
in   length. 

Megalopyge  opercularis  has  the  fifth  ocellus  rather  distant  from 
the  fourth  and  the  crochets  and  verrucae  as  in  Lagoa,  The  dorsal  setae 
of  the  ninth  and  tenth  abdominal  segments,  however,  are  twice  as  long 
as  those  of  the  first  eight  segments  and  form  a  conspicuous  tail. 

Family   CocHLionDAE. 

In  tables  it  is  rather  difficult  to  separate  the  slug  caterpillars  from 
the  larvae  of  other  Holometabola,  but  in  nature  the  thick,  short,  fleshy 
body  and  the  minute  thoracic  legs  will  distinguish  these  forms  from 
all  others.  It  should  be  remembered  that  there  are  no  prolegs  but  that 
the  thoracic  legs  are  always  present.  The  different  genera  seem  to  have 
little  in  common  except  the  small  retractile  form  of  head.  The  arma- 
ture has  developed  from  verrucae,  altho  it  often  includes  scolus-like 
structures.     Some  of  the  genera  are  entirely  smooth. 


98  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [98 

A  synopsis  of  the  American  species  of  this  family  is  given  as  the 
conclusion  of  a  series  of  papers  by  Dyar  in  1899.  It  will  be  found  in 
Jour.  N.  Y.  Ent.  Soc.  8,  1899,  p.  235. 

Family  Lacosomidae. 

Head  rugose,  wider  than  prothorax  and  much  higher,  with  vertex 
on  same  level  as  dorsum  of  body  but  with  ventral  portion  produced  as 
far  as  the  thoracic  legs  are  long ;  ocelli  all  rather  close  together ;  labrum 
with  a  small  notch;  no  secondary  setae.  Body  widest  at  proleg-bearing 
segments,  sometimes  fusiform.  Prothorax  with  epsilon  below  alpha  and 
gamma,  rho  moved  forward  to  a  position  near  it ;  Kappa  group  bisetose. 
Mesothorax  as  usual.  Alpha  of  abdomen  nearer  dorsomeson  than  beta 
on  segments  1  to  9;  kappa  and  eta  adjacent;  Pi  group  consisting  of 
two  to  three  setae  on  segments  1  and  2,  four  to  eight  setae  on  each 
proleg;  two  setae  on  segments  7  and  8,  and  one  seta  on  segment  9. 
Prolegs  present  on  segments  3  to  6  and  10,  each  of  the  five  pairs  bearing 
a  biordinal  complete  circle  of  crochets. 

Cicinnus  melsheimeri  has  seta  iv  of  the  head  enlarged  and  spatu- 
late,  its  base  as  large  as  an  ocellus;  each  proleg  has  six  to  eight  setae 
on  its  cephalolateral  surface;  the  anal  segment  is  depressed;  and  the 
body  is  much  thicker  in  the  middle  than  at  the  ends. 

Lacosoma  cKiridota  has  seta  iv  of  the  head  normal,  its  base  much 
smaller  than  an  ocellus ;  each  proleg  bears  four  setae  on  its  cephalolateral 
surface;  the  anal  segment  is  scarcely  depressed  and  the  body  is  only 
slightly  thickened  in  the  proleg  region.    L.  arizonica  has  not  been  seen. 

Family   Nolidae. 

Systematists  differ  greatly  in  placing  this  family.  Hampson,  in 
1900,  makes  Nolinae  one  of  the  subfamilies  of  Arctiidae,  which  he  con- 
siders the  highest  family  of  the  entire  order.  A  few  years  later  Dyar 
includes  the  group  in  his  Tineoidea,  close  to  Cochlidiidae,  Megalopygidae, 
etc.  The  latter  position  is  based  on  the  presence  of  but  one  verruca 
(Kappa)  between  Rho  and  mu,  caudoventrad  of  the  spiracle  on  the 
abdomen  (Fig.  60),  it  being  assumed  that  this  verruca  arose  from  a 
coalescence  of  kappa  and  eta.  As  many  Acronyctinae  have  verruca 
kappa  reduced  to  a  single  seta  or  even  absent  (Figs.  65  and  66)  this 
condition  does  not  seem  sufficient  to  prove  conclusively  the  position  of 
the  group. 

Head  smooth,  smaller  than  prothorax,  partially  retractile,  bearing 
primary  setae  only;  front  wider  than  high,  not  reaching  half  way  to 
vertical  triangle;  labrum  notched  to  about  one-third  its  depth;  sixth 
ocellus  usually  at  a  considerable  distance  from  upper  five  which  are  in 
a  semicircle  enclosing  seta  vii;  seta  v  rather  closely  associated  with 


99]  LEPIDOPTEROUS    LARVAE— FR ACKER  99 

first  ocellus  (Fig.  86).  Body  cylindrical,  bearing  verrucae  but  no  secon- 
dary setae  except  on  prolegs.  Prothorax  with  a  large  shield  on  which  the 
dorsal  verrucae  are  united;  mesothorax  bearing  four  verrucae  on  each 
side  in  a  transverse  row.  Abdomen  with  the  verrucae  of  the  Beta, 
Rho,  and  Kappa  groups  present  on  the  first  nine  segments;  in  addition 
segments  1,  2,  3,  and  7  have  mu  and  Pi  in  the  form  of  small  verrucae, 
and  sigma  a  single  seta;  segments  4,  5,  and  6  (Fig.  60)  possess  mu, 
but  the  setae  of  the  Pi  group  are  scattered  over  the  proleg  and  united 
with  sigma;  on  segments  8  and  9  mu  is  wanting  but  Pi  is  present. 
Prolegs  are  present  on  segments  4,  5,  6,  and  10,  only;  crochets  always 
biordinal,  in  a  mesoseries. 

The  various  species  differ  in  the  development  of  the  verrucae,  the 
positions  of  the  ocelli,  and  the  coloration.  Owing  to  lack  of  material 
it  is  not  possible  to  diagnose  genera  at  the  present  time,  especially  as  the 
differences  which  do  exist  overlap  generic  limits.  The  ocellar  groups  of 
two  species  are  shown  in  Figs.  86  and  87. 


100  ILLINOIS  BIOLOGICAL   MONOGRAPHS  [100 


MACROHETEROCERA 

SUPERFAMILY  BOMBYCOIDEA 
Family  Epiplemidae 

Head  about  as  high  as  wide,  slightly  bigibbous,  usually  minutely  ru- 
gose ;  front  extending  about  half  way  to  vertical  triangle ;  labrum  moder- 
ately emarginate ;  no  secondary  setae.  Prothorax  bearing  a  dorsal  plate 
with  the  setae  in  the  usual  positions,  epsilon  cephaloventrad  of  rho  above 
spiracle ;  Kappa  and  Pi  groups  each  consisting  of  two  setae ;  mesothorax 
and  metathorax  normal.  Abdomen  (Fig.  62)  with  kappa  and  eta  at 
about  the  same  level  below  the  spiracle,  close  together  on  segmrents  1 
to  3,  farther  apart  on  segments  4  to  8;  mu  always  associated  with 
lambda,  an  additional  subprimary ;  Pi  group  represented  by  one  seta  on 
segment  1,  two  setae  on  segment  2,  four  setae  on  the  prolegs  of  seg- 
ments 3  to  6,  and  one  seta  on  segments  7  to  9 ;  segment  9  with  alpha 
below  level  of  beta  and  as  far  from  it  as  from  rho.  Kappa  and  Pi  groups 
each  represented  by  one  seta.  Prolegs  with  the  planta  semicircular,  the 
band  of  crochets  so  curved  as  to  be  similar  to  a  penellipse,  crochets  bi- 
ordinal.  Spiracles  elliptical,  those  of  the  prothorax  and  abdominal  seg- 
ment 8  twice  as  high  and  wide  as  those  of  the  other  abdominal  segments. 

Four  genera  of  this  family  are  found  in  North  America,  only  two 
of  them  occurring  east  of  the  Rocky  Mountains.  In  CalUzzia  inornata, 
setae  rho,  kappa,  and  eta  on  segment  8  are  about  twice  as  far  from  the 
enlarged  spiracle  of  that  segment  as  the  spiracle  is  high,  and  the  color- 
ation consists  principally  of  a  dark  band  through  the  setae  rho,  shading 
off  to  lighter  brown  above ;  the  ventral  half  of  the  body  is  pale ;  the  head 
is  smooth  and  shining.  In  Calledapteryx  dryopterata,  setae  rho,  kappa, 
and  eta  are  all  closer  to  the  spiracle  than  the  spiracle  is  high,  the  color- 
ation is  paler  and  more  indefinite,  and  the  head  is  often  coarsely  rugose. 

Family  Geometridae. 

Limits  of  time  and  space  forbid  a  discussion  of  the  "loopers"  or 
*' inch-worms".  There  seems  to  be  sufficient  variation  in  the  armature, 
setae,  and  number  and  position  of  prolegs  to  warrant  the  belief  that  a 
separation  of  the  genera  is  possible.    As  no  other  family  has  the  pro- 


101]  LEPIDOPTEROUS  LARVAE— FRACKER  101 

legs  of  any  of  its  members  reduced  to  two  pairs,  one  ventral  and  one 
anal,  no  difficulty  need  be  encountered  in  placing  the  great  majority  of 
the  species  in  the  proper  family.  The  additional  rudimentary  prolegs 
of  Brephos,  Anisopteryx,  and  a  few  other  genera  are  likely  to  cause 
confusion.  The  larvae  of  this  family  are  distinguished  by  the  following 
characters,  some  of  them  possessed .  by  other  families,  but  when  taken 
together,  completely  diagnostic  of  the  Geometridae, 

Body  usually  slender  and  cylindrical  but  sometimes  bearing  humps, 
processes,  and  protuberances  of  various  kinds  and  shapes ;  only  primary 
setae  present  above  the  level  of  the  spiracle,  but  below  eta  subprimaries 
always  found,  varying  in  number  from  one,  lambda,  to  many,  covering 
the  lateral  half  of  the  proleg.  Prolegs  of  abdominal  segments  3,  4, 
and  5  absent  or,  in  a  few  cases,  rudimentary;  crochets  biordinal,  ar- 
ranged in  a  mesoseries.     (Fig.  63.) 

Family  Platypterygidae. 

Head  about  as  high  as  wide,  obscurely  bigibbous ;  no  secondary  setae 
present.  Prothorax  with  epsilon  and  rho  much  farther  cephalad  than  in 
most  Macrolepidoptera,  Kappa  group  consisting  of  two  setae.  Pi  group 
usually  consisting  of  several  setae  borne  on  a  lateral  fleshy  protuberance ; 
mesothorax  with  all  setae  above  spiracular  level  normal;  below  eta  five 
or  six  setae  are  present  in  various  arrangements,  usually  two  on  a  level 
with  mu  of  the  abdomen  and  several  in  a  group  at  the  base  of  the  leg 
forming  the  Pi  group ;  metathorax  similar.  Abdomen  with  alpha  and 
beta  separate,  epsilon  and  rho  separate  dorsad  of  spiracle,  kappa  cau- 
dad  of  spiracle,  and  eta  below;  mu  present;  three  setae  at  base  of  pro- 
leg  and  three  more  on  its  lateral  surface;  segment  9  various.  Setae 
usually  borne  on  small  chalazae,  with  great  variation  on  ventral  half  of 
body,  tho  never  very  numerous.  Prolegs  of  segments  3  to  6  with  the 
planta  circular,  the  crochets  biordinal  or  uniordinal,  arranged  in  a 
pseudocircle  (Fig.  97),  with  the  mesoseries  extending  about  half  way 
round  the  proleg,  the  lateral  series  shorter,  with  smaller  crochets,  not 
continuous  with  the  mesoseries;  anal  prolegs  wanting.  Suranal  plate 
terminating  in  an  acute  process  (Fig.  89).  Spiracles  elliptical,  those  of 
prothorax  about  twice  as  large  as  those  of  abdominal  segments. 

The  genera,  representatives  of  all  four  of  which  are  in  the  U.  S. 
National  Museum,  may  be  distinguished  by  the  various  shapes  and  sizes 
of  the  processes  bearing  the  setae, 

Eudeilinea.  Metathorax  cylindrical,  smooth  above;  head  not 
bicornute;  crochets  uniordinal.  The  family  Auzatidae,  including  in 
America  only  the  single  species  of  this  genus,  E.  herminiata,  is  consid- 
ered distinct  from  Platypterygidae  in  Comstock's  "Manual  for  the 
Study  of  Insects."     The  absence  of  a  chalaza  from  the  metathorax  of 


1Q2  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [102 

the  larvae  and  the  lack  of  secondary  setae  seem  strongly  to  favor  this 
view. 

Falcaria.  This  contains  the  single  species,  FMUneata.  It  has  a 
pair  of  chalazae  on  the  mesothorax,  another  on  the  metathorax,  and 
another  on  the  second  abdominal  segment.  The  Pi  group  on  the  pro- 
thorax  is  borne  on  a  conspicuous  protuberance,  about  as  long  as  the 
thoracic  legs.  The  setae  beta  of  segment  9  are  closer  together  than 
setae  alpha. 

Drepana.  Chalazae  as  in  Falcaria.  Prothoracic  protuberance  not 
as  long  as  the  thoracic  legs.  The  setae  beta  on  segment  9  are  farther 
apart  than  setae  alpha.  D.  arcuata  from  the  eastern  states  is  dark  red 
above  and  bears  a  pair  of  dorsal  chalazae  on  the  first  abdominal  seg- 
ment. D.  siculifer  from  the  Pacific  coast  is  paler  and  segment  1  is 
without  chalazae. 

Oreta.  Metathorax  bearing  a  single  corniculum  on  dorsomeson 
Head  prominently  bicornute.    Oreta  rosea  was  the  only  species  examined. 

Family  Bombycidae. 

Bomhyx  mori,  the  only  species  of  the  Bombycidae  in  North  America, 
shows  considerable  resemblance  to  a  sphingid  but  scarcely  any  similarity 
to  the  Saturnioidea,  with  which  it  is  often  placed.  The  setae  are  so 
reduced  as  to  be  of  little  value  in  identification.  The  caudal  horn  is 
present.  Other  characters  are  given  in  the  table  for  the  separation  of 
families. 

Family  Lasiocampidae. 

The  larvae  of  the  lasiocampids  are  usually  made  conspicuous  by 
their  large  size,  long  setae  and  bright  colors.  They  are  common  leaf- 
eating  caterpillars  and  some  do  considerable  damage.  The  number  of 
setae  over  the  entire  head  and  body  makes  technical  description  and 
location  in  tables  difficult. 

Head  smaller  than  body,  often  retractile,  usually  depressed ;  secon- 
dary setae  numerous  on  all  parts;  labrum  notched  in  most  species  to 
about  one  half  its  depth,  notch  sometimes  continued  as  a  groove  which 
does  not,  however,  extend  to  the  clypeus.  Prothorax  usually  bearing 
one  or  two  blunt,  fleshy  protuberances  just  above  the  legs,  sometimes 
reduced  to  mere  swellings;  other  segments  of  body  sometimes  bearing 
similar  swellings.  Protuberances  always  present  when  the  body  setae  are 
short  and  sparse,  otherwise  the  setae  are  extremely  irregular  in  length, 
ranging  from  very  short  to  as  long  as  the  body  is  wide ;  setae  never  in 
pencils  or  verricules  or  on  verrucae  or  scoli.  Sometimes  a  gibbosity  or 
blunt  horn  is  found  on  segment  8  on  the  dorsomeson.  Prolegs  present 
on  segments  3,  4,  5,  6,  and  10  as  usual;  crochets  biordinal,  arranged  in 
a  mesoseries. 


103]  LEPIDOPTEROUS  LARVAE  — FR ACKER  103 

The  genera  may  be  distinguished  as  follows: 

a.  Body  not  bearing  prominent  lateroventral  protuberances. 

b.  Body  depressed ;  head  depressed,  partially  retractile.     Heteropacha 
bb.  Body  cylindrical ;  dorsal  setae  as  long  as  lateral  setae. 

e.  Head  black,  with  epicranial  suture  inconspicuous;  labral  notch 

always  deep.  Malacosoma 

cc.  Head   with   epicranial   suture    forming   a    conspicuous   yellow 

inverted  Y  on  the  black  background,  or  with  pale  lateral  areas ; 

labrum  sometimes  only  shallowly  emarginate  at  apex. 

Gloveria 

aa.  Body  bearing  conspicuous  lateroventral  protuberances,  longest  on 

prothorax,  where  they  are  proleg-like ;  longest  setae  situated  on  these 

protuberances,  dorsal  setae  very  short  or  absent. 

b.  Body  segments  each  with  a  pair  of  verruca-like  swellings  on  the 

dorsum,  those  of  segment  8  subequal  in  size  to  those  of  other 

segments.  Tolype 

bb.  Body    segments    without    paired    dorsal    verruca-like    swellings, 

but  a  short  fleshy  dorsal  horn  on  segment  8.  Epicnaptera 

Heteropacha  rileyana  is  small  and  onisciform  in  shape.  It  is  more 
closely  related  to  Tolype  than  to  Malacosoma,  but  the  fleshy  processes 
are  reduced. 

Of  Malacosoma,  eight  species  are  found  in  the  United  States.  Most 
of  them  are  large  and  cylindrical  caterpillars  with  long  setae.  There  is 
considerable  variation  in  color.  A  table  of  the  species  has  been  written 
by  Dyar  and  will  be  found  in  the  Canadian  Entomologist,  25,  1893, 
p.  43. 

Gloveria  arizonensis  and  G.  howardi,  the  only  species  of  this  genus 
examined,  overlap  Malacosoma  in  most  characters.  In  arizonensis  the 
labrum  has  a  very  shallow  emargination,  while  in  the  other  species  it  is 
notched  to  about  one-half  its  depth. 

Tolype  velleda  has  the  body  very  much  depressed  and  this  appear- 
ance is  increased  by  the  long  setae  between  the  spiracles  and  prolegs. 
The  venter  is  almost  naked.  The  setae  are  grayish  brown  and  the  body 
is  inconspicuously  marked  except  for  a  dorsal  black  transverse  vitta  on 
the  metathorax.  The  dorsal  metathoracic  verrucae  are  more  prominent 
than  those  of  any  other  segment.  Tolype  laricis  is  similar,  except  that 
the  verrucae  of  the  metathorax  are  not  increased  in  size. 

Epicnaptera  americana  is  a  large  species  with  the  setae  reduced 
in  size  in  the  later  stages.  The  prothoracic  protuberances  on  each  side 
are  very  large. 

Family  Eupterotidae 

This  European   family  includes  the   American   genus  Apatelodes, 


104  ILUNOIS  BIOLOGICAL  MONOGRAPHS  [104 

usually  but  incorrectly  listed  with  Notodontidae.  Numerous  genera  of 
the  family  are  found  in  Europe  and  Asia. 

Head  about  as  high  as  body,  not  retractile,  about  as  ^vide  as  high; 
labral  notch  deep,  either  reaching  two-thirds  distance  to  clypeus  or 
continued  as  a  groove  which  reaches  clypeus;  front  extending  about 
one-third  the  distance  to  the  vertical  triangle;  head  densely  covered 
with  secondarj^  setae,  thrown  back  so  that  the  mouth  parts  are  directed 
almost  cephalad.  Body  cylindrical,  covered  with  numerous  secondary 
setae,  some  short,  others  much  longer,  no  fleshy  protuberances  or  ver- 
rucae  present ;  mediodorsal  setae  usually  grouped  into  a  distinct  tuft 
on  each  segment,  sometimes  forming  long  pencils;  setae  longer  in  tho- 
racic than  in  abdominal  region  and  on  ventral  part  of  abdomen  than 
on  dorsal.  Prolegs  present  on  segments  3,  4,  5,  6,  and  10  as  usual,  those 
of  the  anal  segment  similar  to  the  others;  crochets  biordinal. 

Apatelodes  torrefacta  has  the  body  densely  setiferous,  the  setae 
long  and  soft.  Conspicuous  pencils  are  borne  on  the  dorsomeson  of 
the  last  two  thoracic  and  the  eighth  abdominal  segments.  The  labrum 
is  emarginate  to  about  two-thirds  its  depth.  A.  angelica  is  more  quietly 
colored,  being  a  grayish  brown.  The  setae  of  the  dorsomeson  are  com- 
paratively short,  but  grouped  in  a  small  tuft  on  each  body  segment; 
no  pencils  are  present.  The  labrum  is  emarginate  about  half  its  depth 
and  the  notch  is  continued  to  the  clypeus  in  the  form  of  a  shallow 
groove. 

Family  Liparidae 

The  caterpillars  of  the  tussock  moth  family  may  be  divided  into 
two  groups,  those  of  the  first  resembling  arctians,  those  of  the  second 
having  an  individuality  all  their  ovm.  Both  divisions  bear  dorsal  ever- 
sible  glands  on  abdominal  segments  6  and  7. 

The  genera  of  the  first  group  have  typical  verrucae,  the  arrange- 
ment as  in  Arctiidae  and  Acronycta,  except  that  there  are  three  ver- 
rucae above  the  Kappa  group  on  the  mesothorax  and  metathorax.  The 
usual  variation  in  regard  to  kappa  on  the  abdomen  is  to  be  observed, 
tho  the  fusion  with  rho  in  Porthetria  dispar  is  unique.  The  separation 
or  contiguity  of  alpha  and  beta  is  merely  incidental  to  the  amount  of 
development  of  these  verrucae  and  the  area  they  occupy. 

Group  two  is  a  contrast  to  the  commonplace  larvae  of  the  first 
division,  being  bizarre  in  color  and  armature.  The  long  pencils  are 
composed  of  peculiar  setae  with  spurs  much  longer  near  the  tip  than 
at  the  base.  This  gives  a  clavate  appearance,  altho  the  seta  is  not  itself 
swollen.  The  locations  of  these  " clavate-plumed  setae"  are  good  taxo- 
nomic  characters. 


105]  LEPIDOPTEROUS  LARVAE— FR ACKER  105 

Genera  of  Liparidae : 

a.  Body  bearing  tufted  setae  but  no  long  pencils  or  dense  verricules. 
b.  Abdominal   segments  bearing  a  single  large  verruca,  eta,  below 
spiracle,  with  a  very  small  one,  mu,  behind  it;  verruca  rho  fused 
with  kappa  dorso-caudad  of  the  spiracle ;  verruca  alpha  on  ab- 
domen distinct,  tho  small.  Porthetria 
bb.  Abdominal  segments  bearing  two  large  verrucae  below  spiracle, 
mu  directly  below  eta;   kappa,   when  present,   distinct,   behind 
spiracle;  verruca  alpha  fused  with  beta, 
cc.  Verruca  kappa  present  and  distinct,  tho  small;  body  bearing 
some  very  feathery  setae.                                             Gynaephora 
cc.  Verruca  kappa  absent  or  indistinct;  setae  echinulate  but  not 
feathery.  Euproctis 
aa.  Body  bearing  a  pair  of  long  pencils  of  setae  on  prothorax  and  a 
mesal  pencil  on  segment  8. 
b.  First   four   abdominal   segments   bearing   dense   dorsal   verricules 
very  different  from  verrucae  of  other  segments, 
c.  Clavate-plumed  setae  present  on  all  or  nearly  all  segments. 

(In  part)     Olene 

cc.  Clavate-plumed  setae  present  only  in  the  tufts  of  the  prothorax 

and  eighth  abdominal  segment  and  sometimes  on  the  second 

abdominal  segment.  Hemerocampa 

Notolophus 

bb.  First  four  abdominal  segments  bearing  verrucae  similar  to  those 

of  other  segments.  (In  part)    Olene 

Porthetria  includes  a  single  species,  the  Gipsy  moth,  P.  dispar. 

Euproctis  chrysorrhea  is  the  Browntail  moth  and  is  the  only  spe- 
cies of  this  European  genus  as  yet  introduced  into  America. 

The  characters  given  for  Gynaephora  in  the  synopsis  refer  to  G. 
rossiiy  the  larva  of  which  differs  greatly  from  G.  groenlandica.  The 
latter  species  occurs  only  in  the  Arctics. 

Oleiie  achatina  differs  from  other  members  of  the  second  group  in 
the  absence  of  verricules  on  the  first  four  abdominal  segments.  The 
setae  densely  cover  all  parts  of  the  body.  Clavate-plumed  setae  are 
present  only  on  the  prothorax.  0.  leucophaea,  0.  pini  Dyar,  and  0. 
plagiata  are  more  similar  to  the  common  Tussock  moth. 

Hemerocampa  and  Notolophus  overlap  and  the  larvae  can  not  be 
distinguished.  N.  antiqua  differs  from  the  others  in  the  presence  of 
clavate-plumed  setae  on  abdominal  segment  2.  The  others  may  be  sepa- 
rated by  the  table  given  by  Dyar  in  Psyche,  7,  1893,  p.  421. 


106  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [106 

Family  Thyatiridae 

Head  vertical,  wider  than  high;  front  small;  adf rentals  distinct; 
no  secondary  setae;  labrum  usually  notched  to  about  two-thirds  its 
depth,  sides  of  notch  parallel.  Body  cylindrical,  not  bearing  secondary 
setae;  primary  and  subprimary  setae  arranged  as  described  for  Epi- 
plemidae  except  that  the  Pi  group  on  the  prolegs  consists  of  three  setae 
only  and  of  at  least  two  setae  on  segments  1,  2,  7,  and  8.  Ventral  pro- 
legs  bearing  biordinal  crochets  in  a  curved  mesoseries;  anal  prolegs 
reduced  to  one-half  or  two-thirds  size  of  ventral. 

Hdbrosyne  rectangulata  has  the  head  shining  and  the  Pi  group 
on  the  mesothorax  and  metathorax  bisetose.  In  H.  scripta  the  head  is 
more  or  less  dull  and  minutely  rugose,  the  dorsal  half  of  the  abdomen 
bears  diagonal  stripes,  and  the  Pi  group  on  the  last  two  thoracic  seg- 
ments is  unisetose. 

Pseudothyatira  expultrix  and  P.  cymatophoroides  each  show  a  dull- 
and  rugose  head  and  unmarked  body.  The  Pi  group  is  bisetose  on  each 
thoracic  segment. 

Family  Notodontidae 

Larvae  of  this  family  are  usually  identified  at  a  glance  by  their 
peculiar  decoration  and  shapes.  A  student  of  the  larval  stage  can  not 
accede  to  Hampson's  view  that  the  arctians,  noctuids,  and  syntomids 
are  specialized  modifications  of  the  notodontian  type,  or  that  Notodon- 
tidae are  a  generalized  family.  All  the  species  have  secondary  setae 
on  the  sides  of  the  prolegs  and  specialized  anal  prolegs,  thus  departing 
widely  from  the  generalized  condition  retained  by  Noctuidae. 

Many  species  of  the  subfamily  Notodontinae  will  trace  to  Noctuidae 
in  any  tables  hitherto  published.  The  setiferous  prolegs  will  serve  to 
distinguish  in  most  of  these  cases.  Other  characters  are  given  in  the 
table  for  the  separation  of  the  families.  The  subfamilies  may  be  recog- 
nized by  the  following  key : 

a.  Body  bearing  numerous  secondary  setae,  obscuring  primary  ones; 
anal  prolegs  not  increased  in  size, 
b.  Head  bearing  numerous  short,  fine,   secondary  setae ;  abdominal 
segments  1  and  8  often  bearing  conspicuous  dorsal  cornicula. 

Melalophinae 
bb.  Head  without  secondary  setae;  dorsal  cornicula  never  present. 

Pygaerixae 
aa.  Body  bearing  only  primary  setae  above  level  of  prolegs;  anal  pro- 
legs  usually  elongated, 
b.  Dorsum  of  thorax  consisting  of  a  broad  flattened  triangle  with 
conspicuous  lateral  pro  thoracic  and  mesal  metathoracic  angles; 
anal  prolegs  long;  head  small,  partially  retractile.        Cerurinae 


107]  LEPIDOPTEROUS  LARVAE  — FRACKER  107 

bb.  Dorsum  of  thorax  not  flattened  nor  triangular;  anal  prolegs  not 
greatly  elongated ;  head  usually  as  large  as  prothorax. 

NOTODONTINAE 

Melalophinae.  This  subfamily  includes  the  one  genus  Melalopha 
(lehthyura).  The  six  species  may  be  distinguished  by  the  characters 
given  by  Packard,  (1895). 

Pygaerinae.  The  larvae  of  Datana  are  well  known  in  all  parts  of  the 
United  States.  As  the  colors  change  at  each  molt  the  species  are  hard 
to  separate.  Packard  gives  a  key  to  them  which  may  be  used  with  more 
or  less  success,  and  his  figures  are  invaluable.  He  was  acquainted  with 
the  larvae  of  all  described  species  except  rohusta,  modesta,  and  chiri- 
quensis.  D.  rohusta  is  very  similar  to  D.  contracta  but  the  stripes  are 
dark  brown  instead  of  creamy  white  and  the  prothoracic  shield  is  black 
instead  of  yellow  in  the  last  instar. 

Cerurinae.  Two  genera,  Harpyia  and  Cerura,  whose  larvae  are 
very  similar,  compose  this  group.  The  long  stemapoda,  or  modified 
anal  prolegs,  distinguish  them  at  a  glance  from  other  Notodontidae. 
In  Cerura  scitiscripta  the  metathorax  has  a  single  median  prominence, 
and  in  C.  occidentalis  there  is  a  bifurcate  one.  The  metathorax  of  the 
species  of  Harpyia  is  without  prominences.  All  have  a  dorsal  reddish 
somewhat  broken  vitta  running  the  entire  length  of  the  body  and  reach- 
ing in  some  places  as  far  ventrad  as  the  spiracle.  In  H.  cinerea  this 
vitta  is  wanting  on  the  metathorax  but  in  the  other  two  species  it  is 
continuous  from  thorax  to  abdomen.  Its  lateral  margins  are  convex 
on  the  mesothorax  of  H.  scolopendrina  and  concave  in  H.  horealis. 

Notodontinae.  At  first  glance  the  genera  which  are  grouped  to- 
gether under  this  name  seem  rather  heterogeneous.  The  wing  venation 
of  the  adults  is  as  various  as  the  form  of  the  larvae.  Nevertheless  a 
logical  separation  of  Gluphisia  and  the  Heterocampinae  seems  almost 
impossible.  The  former  is  very  closely  related  to  some  of  the  Notodon- 
tinae as  Packard  limited  the  group.  The  species  of  Heterocampa  form 
a  series  of  transition  stages  from  typical  notodontians  to  the  peculiarly 
specialized  larvae  of  Schizura  and  Hyparpax.  This  is  in  striking  con- 
trast to  the  distinct  separation  of  the  Pygaerinae  and  the  Ichthyurinae 
from  other  members  of  the  family.  The  long  stemapoda  in  early  stages 
of  Fentonia  (Macrurocampa)  seem  to  indicate  that  even  Cerura  and 
Hayrpia  should  be  included  here.  Other  structures,  however,  make  the 
line  of  separation  distinct.  The  various  genera  may  be  distinguished  by 
means  of  the  following  synopsis.  The  comparative  clause  in  the  first 
division  is  due  to  the  peculiar  dorsal  series  of  gibbosities  of  Nerice,  a 
genus  which  clearly  belongs  in  the  second  group. 


108  ILLINOIS  BIOLOGICAL   MONOGRAPHS  [108 

Genera  of  Notodontinse : 

a.  First  abdominal  segment  bearing  a  higher  dorsal  gibbosity  than  sec- 
ond, gibbosity  usually  either  bifurcate  or  bearing  a  pair  of  cor- 
nicula. 
b.  Dorsal  corniculum  of  segment  8  single,  that  of  segment  1  obscurely 
bifurcate.  lanassa 

bb.  Dorsal  corniculum  of  segments  1  and  8  distinctly  bifurcate, 
c.  Segments  4  and  5  not  gibbous  above;  color  between  humps  on 
segments  1  and  8  mainly  in  a  single  elliptical  patch;  labrum 
notched  to  two-thirds  its  depth.  Hyparpax 

cc.  Segments  4  and  5  usually  gibbous  above ;  color  between  seg- 
ments 1  and  8  never  in  a  distinct  elliptical  patch;  labrum  not 
notched  to  two-thirds  its  depth.  Schizura 

aa.  First  abdominal  segment  not  bearing  a  higher  dorsal  gibbosity  than 
second;  gibbosity,  when  present,  neither  bifurcate  nor  bearing  a 
pair  of  cornieula. 
b.  Segment  8  bearing  a  distinct  dorsal  hump  or  horn  or  pair  of  cor- 
nieula. 
c.  Dorsal  processes  of  segment  8  slender,  horn-like. 

d.  Horn  single,  similar  to  the  caudal  horn  of  a  sphingid. 

Pheosia 
dd.  Horns  paired,  slender  and  sharply  pointed.  Ptilodon 

cc.  Dorsal  hump  of  segment  8  broad,  not  horn-like, 
d.  Segment  2  conspicuously  gibbous  above. 

e.  Abdomen  bearing  high  dorsal  gibbosities  on  eight  segments. 

Nerice 
ee.  Abdomen  bearing  dorsal  humps  on  not  more  than  five  seg- 
ments. (In  part)    Hyperaeschra 
dd.  Segment  2  not  gibbous  above. 

e.  Segment  8  swollen  and  discolored  over  entire  dorsal  half; 
coloration  mainly  a  series  of  longitudinal  stripes. 

Symmerista 
ee.  Segment  8  not  swollen  over  entire  dorsal  half. 

f.  Anal  prolegs  short  and  rounded;  coloration  in  indefinite 
transverse  stripes.  Odontosia 

ff.  Anal  prolegs  usually  elongate. 

g.  Head  bearing  a  pair  of  dark  dorsal  spots.  Ellida 

gg.  Head  unicolorous. 

h.  Coloration   principally  a  series  of  conspicuous  lon- 
gitudinal  stripes   on   dorsal  half  of  each   segment 
and  rounded  spots  at  base  of  each  leg.     Dasylophia 
]  hh.  Coloration  principally  a  series  of  conspicuous  trans- 


109]  LEPIDOPTEROUS  LARVAE  — FR ACKER  109 

verse  stripes  on  dorsal  half  and  longitudinal  stripes 
on  ventral  half  of  body.  Didugua 

bb.  Segment  8  not  bearing  a  distinct  dorsal  hump,  horn,  or  gibbosity. 
c.  Prothorax  bearing  a  pair  of  dorsal  eornicula. 

d.  Anal  prolegs  stemapodiform,  about  as  long  as  body  is  wide^ 
longer  in  early  stages.  Fentonia 

dd.  Anal  prolegs  shorter  than  body  is  wide. 

e.  Head  divided  by  a  pair  of  subvertical  lines  into  three  areas, 
the  lateral  minutely  rugose,  the  mesal  hard  and  shining. 

(In  part)    Heterocampa 
ee.  Head  not  divided  into  three  areas.  Litodonta 

CO.  Prothorax  not  bearing  a  pair  of  dorsal  eornicula. 

d.  Body  bearing  a  distinct  lateral  line  through  spiracles  or  a 
conspicuous  mediodorsal  line  or  both;  supraspiraeular  lines 
never  present, 
e.  Prothoracic  spiracle  conspicuous,  about  twice  the  height  of 
the  abdominal  spiracles;  second  ocellus  closer  to  first  than 
to  third, 
f.  Kappa  on  segments  5,  6,  and  8  separated  from  the  spira- 
cle by  a  distance  equal  to  about  one-half  the  width  of 
the  spiracle.  (In  part)  Hyperaeschra 

ff.  Kappa  on  segments  5,  6,  and  8  separated  from  the  spira- 
cle at  least  as  far  as  the  spiracle  is  wide.       Lophodonta 
ee.  Prothoracic  spiracles  about  the    same    size    as    abdominal 
spiracles  or  not  more  than  one  and  a  half  times  as  high, 
f .  Lateral  lines  present ;  second  ocellus  closer  to  first  than  to 
third;  dorsal  line  double.  Gluphisia 

ff.  Lateral  lines  not  present;  second  ocellus  closer  to  third 
than  to  first;  dorsal  line  single.  Misogada 

dd.  Body  not  bearing  lateral  lines  through  spiracles;  mediodor- 
sal line  when  present  paralleled  by  a  pair  of  supraspiraeular 
lines  on  at  least  a  part  of  the  abdomen, 
e.  Second  and  third  ocelli  closer  together  than  first  and  second ; 
anal  plate  usually  inconspicuous,  all  spiracles  subequal  in 
size.  (In  part)    Heterocampa 

ee.  Second  and  third  ocelli  as  far  apart  as  first  and  second; 
anal  plate  large,  semicircular,  nearly  as  wide  as  segment 
9 ;  spiracles  of  prothorax  much  larger  than  those  of  abdo- 
men. Nadata 

A  discussion  of  the  genera  of  this,  the  largest  subfamily,  would  be 
out  of  place  in  a  paper  of  this  kind  in  view  of  the  excellent  Monograph 
by  Packard,  but  as  several  species  have  been  described  since  the  publi- 
cation of  that  work,  the  following  notes  are  offered: 


110 


ILLINOIS  BIOLOGICAL  MONOGRAPHS 


[110 


lanassa  lignicolor,  in  all  except  the  last  stage,  is  very  similar  to 
Schizura  unicornis.  The  striped  head,  with  three  mesal  white  marks 
in  a  vertical  row,  will  distinguish  it,  the  head  of  S.  unicornis  being 
unicolorous  red. 

Ptilodon  americana  is  called  Odontosia  camelina  by  Packard.  The 
larva  is  very  distinct  from  Odontosia  elegans. 

Hyperaeschra  shauld  apparently  be  divided  into  two  genera,  for 
the  larvae  of  H.  georgica  and  H.  stragula  are  very  different. 

Didugua  Druce  was  erected  for  the  species  argentilinea  Druce, 
found  in  Texas.     The  coloration  is  distinctive. 

The  following  species  of  Notodontidae  were  examined: 
Melalopha — all  listed  species 


Datana  ministra 
D.  californica 
D.  angusii 
D.  drexelii 
D.  major 
D.  palmii 
D.  floridana 
D.  perspicua 
D.  rohusta 
D.  integerrima 
D.  contracta 

Cerura  scitiscripta 
C.  occidentalis 

Uarpyia  cinerea 
H.  horealis 
H.  scolopendrina 

lanassa  lignicolor 

Hyparpax  aurora 

H.  perophoroides 

Schizura  ipomoeae 
8.  concinna 
S.  semirufescens 
8.  unicornis 
8.  apicalis 
8.  hadia 
8.  leptinoides 
8.  errucata  Dyar 


Pheosia  dimidiata 
Ptilodon  americana 
Nerice  hidentata 
Hyperaeschra  stragula 

H.  georgica 
Symmerista  alhifrons 
Odontosia  elegans 
Ellida  caniplaga 
Dasylophia  anguina 
Didugua  argentilinea  Druce 
Fentonia  marthesia 
Heterocampa  ohliqua 

H.  picta 

H.  umbrata 

H.  manteo 

H.  hiundata 

H.  guttivitta 

H.  hilineata 
Litodonta  hydromeli 
Lophodonta  ferruginea 

L.  angulosa 
Gluphisia  septentrionalis 
Misogada  unicolor 
ffadata  gibhosa 


Family  Dioptidae 


Phryganidia  californica,  the  only  species  of  this  family  found  in 
North  America,  is  described  and  figured  by  Kellogg  and  Jackson  in 


Ill]  LEPIDOPTEROUS  LARVAE  — FR ACKER  111 

Proc.  Cal.  Acad.  Sci.  (2)  5,  1895,  p.  563.  The  larva  is  noctuiform  and 
cylindrical  with  all  the  usual  prolegs  present  altho  the  anal  ones  are 
slightly  reduced  in  size.  The  primary  setae  are  reduced,  but  easily 
located  with  a  lens;  secondary  setae  are  present  only  on  the  prolegs. 
Labrum  acutely  tho  not  very  deeply  notched,  as  in  most  Notodontidae. 
The  cuticular  projections  of  the  body  are  conspicuous  under  a  magnifi- 
cation of  about  two  hundred  but  might  be  overlooked  with  a  low  power 
objective.  The  color  is  green,  with  longitudinal  black  stripes.  This 
insect  is  not  found  east  of  California. 

Family  Pericopidae 

Head  rarely  or  never  bearing  secondary  setae;  thoracic  segments 
always  with  sigma  large  and  distinct,  close  to  the  coxae ;  verrucae  alpha 
and  beta  of  abdomen  never  contiguous ;  verruca  kappa  of  abdomen  never 
reduced,  always  much  lower  on  segment  7  than  on  segments  6  and  8; 
mesothorax  bearing  either  one  or  two  verrucae  above  that  of  the  Kappa 
group.    Otherwise  closely  similar  to  Syntomidae  (Figs.  67,  68). 

The  larvae  of  the  American  genera  and  species  of  this  family  are 
described  by  Dyar  (1914). 

Family  Nycteolidae 

This  family,  as  such,  has  been  abandoned  by  Hampson  and  other 
recent  lepidopterists.  There  is  certainly  no  larval  justification  for  its 
separation  from  Noctuidae,  altho  the  position  of  seta  vii  on  the  head 
seems  to  be  closer  to  the  second  and  farther  from  the  third  ocellus  than 
in  other  noctuid  genera.  Calling  the  group  "subfamily  Sarrothripi- 
nae",  as  Hampson  does,  seems  best  to  suit  the  facts  of  both  larval  and 
adult  structure. 

Family  Noctuidae 

The  Owlet  moths  include  about  one-half  of  the  nearly  seven  thou- 
sand described  species  of  Lepidoptera  in  North  America.  A  uniform 
group  of  this  size  naturally  presents  great  problems  to  the  systematist 
and  takes  an  amount  of  time  disproportionate  even  to  the  size  of  the 
family.  By  far  the  majority  of  the  unidentified  and  misidentified  moths 
in  the  museums  of  the  world  probably  belong  to  Noctuidae.  The  monu- 
mental work  of  Hampson,  which  is  still  in  course  of  publication,  is 
doing  much  to  clear  up  questions  of  classification;  but  no  amount  of 
discussion  can  make  a  problem  of  this  size  easy  of  solution. 

In  the  larvae  the  difficulties  facing  the  taxonomist  are  intensified. 
With  the  exception  of  half  a  dozen  genera,  noctuid  larvae  are  so  uni- 
form in  structure  that  one  can  often  compare,  part  by  part,  every  seg- 
ment   and    appendage    of    larv«e    of    two    species    without    finding    a 


112  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [112 

difference  either  of  kind  or  of  degree.  On  the  other  hand  the  half-dozen 
exceptions  include  species  which  resemble  arctians,  lasiocampids,  noto- 
dontids,  eupterotids,  etc.,  and  which  have  been  distributed  by  some 
authors  into  a  variety  of  families.  Naturally  it  is  the  latter  forms 
which  are  most  difficult  to  handle  in  a  synopsis  of  the  entire  order  but 
which  are  easy  to  separate  from  each  other. 

It  is  not  a  part  of  the  plan  of  this  paper  to  enter  the  subject  of  the 
classification  of  Noctuidae.  The  range  must,  however,  be  considered. 
Many  of  the  larvae  are  of  such  structure  that  they  will  not  trace  to  the 
correct  family  in  any  tables  hitherto  published.  It  is  clear  that  differ- 
ent characters  must  be  used  in  identification  according  as  the  setae  are 
primary  or  secondary  or  developed  into  tufts,  the  crochets  biordinal 
or  uniordinal,  and  the  body  cylindrical  or  with  prominent  humps.  We 
must  then  divide  the  family  into  four  groups,  of  which  the  first  will 
include  nearly  all  the  genera,  most  of  the  larvae  being  of  the  "cut- 
worm" type,  and  the  others  will  be  confined  to  the  genera  Demas,  Pan- 
thea,  Acronycta,  Harrisimemna,  Agriopodes,  Polygrammate,  and  a  few 
others  of  minor  importance.  Larvae  of  Acronycta  will  be  found  in  all 
groups  except  the  first,  but  species  of  the  other  genera  mentioned  are 
few  in  number  and  individuals  rare.  These  ''groups"  are  purely  for 
convenience  and  do  not  constitute  a  "natural"  arrangement. 

Group  1.  Larvae  with  primary  setae  only;  prothorax  with  beta 
above  level  of  alpha,  epsUon  associated  with  rho  between  delta  and 
spiracle,  Kappa  and  Pi  groups  each  bisetose;  mesothorax  with  alpha 
associated  with  beta,  epsilon  with  rho,  and  kappa  with  eta,  theta  sepa- 
rate. Pi  group  unisetose ;  metathorax  similar.  Abdominal  segments  1 
to  6  and  8  with  alpha  above  level  of  beta,  rho  above  level  of  spiracle; 
epsilon,  when  present,  smaller,  and  located  cephalodorsad  of  spiracle, 
kappa  and  eta  widely  separated,  mu  present.  Pi  group  consisting  of 
three  setae  on  most  segments;  sigma  present;  no  other  setae  present 
except  sometimes  a  few  members  of  the  Tau  group  and  sometimes 
gamma ;  segment  7  similar,  except  that  kappa  is  always  much  lower  and 
closer  to  eta;  segment  9  with  alpha,  beta,  and  rho  forming  a  triangle, 
kappa,  eta,  mu,  pi,  and  sigma  present.  Prolegs  present  on  segments  5, 
6,  and  10,  at  least,  and  usually  on  segments  3  and  4;  crochets  arranged 
in  a  mesoseries,  uniordinal  except  in  some  Plusiinae  and  others,  in  which 
the  crochets  are  biordinal.  This  group  contains  the  vast  majority  of 
genera  but  none  of  the  species  of  Acronycta.     (Figs.  17-24,  29-32.) 

Group  2.  Larvae  with  well  developed  verrucae  (Figs.  65,  66), 
Arrangement  of  tufts  similar  to  that  in  Arctiidae  except  that  kappa  is 
lower  on  segment  7  than  on  segments  6  and  8  (scarcely  lower  in  Cha- 
radra)  ;  in  one-fourth  of  the  species  kappa  is  reduced  to  one  or  a  few 
setae  and  is  easily  overlooked.    The  crochets  of  the  species  of  Acronycta 


113]  LEPIDOPTEROUS  LAWAE  —  FRACKER  113 

are  always  uniordinal  and  the  full  five  pairs  of  prolegs  on  segments  3  to 
6  and  10  are  always  present.  The  notch  of  the  labrum  is  somewhat 
varied,  but,  as  a  rule,  is  deep,  with  parallel  sides  and  a  rounded  bottom. 
Twenty-two  of  the  forty-two  species  of  Acronycta  examined  appear  to 
belong  in  this  group,  as  well  as  Charadra  deridens,  Panthea  furcilla, 
Demas  propinquilinea,  the  species  of  Eulonche,  Simyra,  Polygram- 
mate,  Agriopodes,  and  possibly  a  few  other  Acronyctinae. 

Group  3.  Verrucae  obscured  by  the  development  of  secondary 
setae.  This  large  number  of  secondary  setae  covers  all  the  characters 
ordinarily  used  in  the  identification  of  noctuids  and  necessitates  a 
search  to  find  other  distinguishing  structures.  It  happens,  however, 
that  no  other  multisetiferous  larvae  have  uniordinal  crochets  and  short 
prolegs  except  Datana  and  Melalopha  of  the  Notodontidae,  and  these 
are  so  distinctive  in  appearance  that  there  is  little  danger  of  confusing 
Acronycta  with  them.  The  parallel-sided  notch  of  the  labrum  is  also 
distinctive*.  Fifteen  of  the  species  of  Acronycta  examined  are  of  this 
type. 

Group  4.  Verrucae  reduced  to  single  setae  or  small  or  indefinite 
groups  of  setae  in  the  last  instar  altho  preceded  by  well  developed  tufts 
in  earlier  stages.  In  accordance  with  a  well  recognized  natural  law, 
degeneration  of  a  structure  does  not  result  in  a  condition  exactly  similar 
to  that  from  which  the  structure  arose.  Thus  the  reduction  of  verrucae 
to  single  setae  almost  never  causes  a  complete  return  to  the  generalized 
chaetotaxy.  In  Lithosiidae  this  is  shown  by  the  double  nature  of  Rho 
on  the  abdomen  and  of  Pi  on  the  mesothorax  and  metathorax,  and  in 
Arctiidae  by  the  multisetiferous  leg-plate  of  Doa  or  the  bisetose  Pi 
group  on  the  metathorax  of  Utetheisa.  Both  these  latter  conditions  are 
found  in  that  anomalous,  notodontid-like,  noctuid  genus  Harrisimemna. 
In  the  Acronyctas,  however,  the  leg-plate  seems  to  have  been  reduced  to 
three  setae  and  the  Pi  group  on  the  metathorax  to  one  seta  at  the  same 
time  that  alpha,  beta,  rho,  etc.,  degenerated  from  verrucae  to  single 
setae.  It  is  a  strange  fact  that  mu  has  not  followed  the  same  course  but 
retains  its  multisetiferous  condition  as  a  well  developed  verruca.  This 
is  true  of  all  the  "single-haired"  Acronycta  larvae  examined,  viz.,  A. 
exilis,  A.  haesitata,  A.  afflicta,  and  A.  funeralis. 

In  any  synopsis  of  the  larvae  for  purposes  of  identification,  the 
four  groups  must  be  handled  separately  in  spite  of  the  fact  that  they 
have  all  been  derived  from  the  same  type.     They  are  listed  above  in 


*The  labrum  of  Acronycta  leporina,  which  belongs  here,  is  figured  by  Forbes 
(ipio)  as  having  a  shallow  notch.  This  does  not  agree  with  the  individuals  of  this 
species  which  I  have  seen  nor  with  any  other  Noctuidae  having  numerous  sec- 
ondary setae  obscuring  the  verrucae,  so  far  as  I  know  them. 


114  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [114 

the  order  in  which  they  seem  to  have  arisen;  first  the  primary  setae, 
then  the  development  of  vemieae,  which  later  became  modified  either 
by  the  addition  of  numerous  secondary  setae,  or  by  reduction  to  almost 
the  primary  chaetotaxy  again.  In  the  absence  of  justification  in  adult 
structure,  it  does  not  seem  best  to  separate  the  last  three  groups  from 
the  first  as  a  distinct  family,  as  has  been  done  by  some  pre\ious  workers. 

Family  Agaristtoae 

This  family  should  meet  the  same  fate  as  Nycteolidae  and  be  in- 
cluded among  the  noctuids.  The  adult  structure  on  which  it  is  based, 
the  clubbed  antennae,  is  so  variable  that  it  is  hard  to  limit  the  group 
exactly.  At  the  same  time  the  larvae  seem  to  be  distinguishable  from 
the  Noctuidae  only  in  color,  nearly  all  the  species  being  transversely 
striped.  The  one  species  found  east  of  the  Rocky  Mountains  and  north 
of  Florida,  Alypia  octomaculata,  may  be  recognized  by  the  humped 
eighth  abdominal  segment,  the  conspicuous  chalazae  and  the  transverse 
stripes.  That  is  the  extreme,  however,  for  the  western  species  form  a 
nearly  complete  series  connecting  Alypia  with  typical  Noctuidae.  The 
following  species  were  examined:  Alypia  octomaculata,  A.  langtanii, 
A.  ridingsii,  Copidryas  gloveri,  C.  cosyra  Druce,  Androloma  mac-cul- 
lochii. 

Family  Arcthdae 

Head  smooth,  bearing  sparse  secondary  setae  or  none;  front  about 
as  wide  as  high,  extending  half  way  to  vertical  triangle ;  labrum  with  a 
rather  wide,  shallow  emargination,  sometimes  acute  at  bottom;  ocelli 
various,  the  fifth  and  sixth  distant  from  the  others.  Body  bearing 
verrucae  except  in  a  few  reduced  genera,  Doa  and  Utetheisa,  in  which 
only  primary  setae  and  a  few  others  remain ;  usual  positions  of  verrucae 
shown  in  Figs.  25  to  28,  33,  and  34.  Verrucae  of  Beta  and  Rho  groups 
of  mesothorax  and  metathorax  never  fused;  Kappa  of  abdominal  seg- 
ments 1  to  8  always  distinctly  present  near  spiracle,  sometimes,  but 
rarely,  slightly  lower  on  segment  7  than  on  segments  6  and  8 ;  prolegs 
with  uniordinal  crochets  in  a  mesoseries,  heteroideous  in  all  but  a  few 
species.     (Fig.  107.) 

The  author  is  not  satisfied  with  the  following  table  of  the  genera 
but  presents  it  in  the  hope  that  it  may  be  of  some  service.  Arctian 
larvae  seem  not  to  possess  constant  characters  of  generic  value. 

a.  Verrucae  reduced  to  chalazae  bearing  single  setae. 

b.  Head  and  thorax  normal  in  size ;  crochets  heteroideous.     Utetheisa 
bb.  Head  very  small,  thorax  swollen;  crochets  homoideous.  Doa 

aa.  Verrucae  not  reduced,  multisetiferous. 


115]  LEPIDOPTEROUS  LARVAE  — FR ACKER  115 

b.  Subdorsal  setae  of  thorax,  at  least  of  metathorax,  twice  as  long  as 
those  of  middle  abdominal  segments,  usually  forming  pencils, 
c.  Verrucae  rho  of  segment  8  of  abdomen  each  bearing  a  long  pencil 
of  setae ;  other  setae  of  segments  8  and  9  short.  Halisidota 

cc.  Verrucae  rho  of  segment  8  not  bearing  longer  setae  than  ver- 
rucae alpha  and  beta, 
d.  Body  and  setae  unicolorous,  never  black.  Ammalo 

dd.  Body  bearing  black,  white,  and  orange  colored  tufts  of  setae 
.  on  the  abdomen.  Euchaetias 

bb.  Subdorsal  setae  of  thorax  subequal  in  length  to  those  of  abdominal 
segments, 
c.  Labrum  notched  to  at  least  half  its  depth. 

d.  Each  verruca  bearing  setae  of  two  distinct  lengths,  the  shorter 

sheared  off  even,  the  others  fewer,  twice  as  long,  irregular 

in  length.  Hemikyalea 

dd.  Each  verruca  bearing  setae  of    only  one    or    of    irregular 

lengths. 

e.  Cuticula  and  setae  pale ;  setae  sheared  off  even ;  size  small. 

Eupseudosoma 
ee.  Cuticula  and  setae  very  dark,  with  pale  transverse  stripes; 
size  very  large.  Ecpantheria 

cc.  Labrum  notched  to  less  than  half  its  depth. 

d.  Thoracic  and  caudal  abdominal  segments  bearing  setae  of  a 
different  color  from  those  of  proleg-bearing  segments, 
e.  Setae  of  four  to  six  middle  abdominal  segments  brown,  those 
of  thorax  and  caudal  abdominal  segments  black.  Isia 

ee.  Setae  of  most  of  abdomen  black,  those  of  thorax  and  end 
of  abdomen  brown.  Platyprepia 

dd.  Thoracic  and  caudal  abdominal  segments  not  bearing  setae 
of  a  different  color  from  those  of  proleg-bearing  segments, 
e.  Each  abdominal  verruca  bearing  setae  of  two  contrasting 
colors,  white   and  black;  cuticula  unicolorous,  without  a 
mediodorsal  stripe, 
f.  White  setae  about  twice  as  long  as  black.  Arctia 

ff.  White  setae  about  same  length  as  others.  Ectypia 

ee.  Each  abdominal  verruca  bearing  setae  of  one  color  only, 
except  when  a  bright  mediodorsal  stripe  is  present, 
f.  Verrucae  alpha  of  abdomen  about  one-third  the  size  of 
verrucae  beta;  all  verrucae  small;  setae  of  segments  8 
and  9  not  longer  than  those  of  other  parts  of  body, 
g.  Verrucae  kappa   of  middle  abdominal    segments    par- 
tially or  entirely  above  level  of  lower  margin  of  spira- 
cle. Apantesis 


116  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [116 

gg.  Verrucae  kappa  of  middle  abdominal  segments  well 
below  level  of  spiracle. 
\  h.  All  abdominal  verrucae  below  level  of  beta  pale,  ver- 

rucae beta  black;  body  marked  with  longitudinal 
stripes.  Hyphantria 

hh.  All  abdominal  verrucae  black;  setae  of  verrucae  rho 
sometimes  forming  pencils ;  no  stripes.         Eubaphe 
ff.  Verrucae  alpha  of  abdomen  about  the  same  size  as  ver- 
rucae beta;  when  distinctly  smaller,  segments  8  and  9 
bear  setae  about  three  times  as  long  as  those  of  other 
segments, 
g.  Segments  1,  2,  and  7  bearing  two  verrucae  at  the  same 
level  in  line  with  verruca  mu  of  segments  3  to   6 ; 
setae  short ;  body  longitudinally  striped.  Haploa 

gg.  Segments  1,  2,  and  7  bearing  only  one  verruca  in  line 
with  verruca  mu  of  segments  3  to  6. 
h.  Subdorsal  setae  of  segments  8  and  9  three  times  as 
;  long  as  those  of  any  other  segments;  over  twice  as 

long  as  body  is  wide.  Leptarctia 

hh.  Subdorsal  setae  of  segments  8  and  9  usually  sub- 
equal  in  length  to  those  of  other  segments,  never 
twice  as  long  as  body  is  wide, 
i.  Labrum  very  shallowly   concave   at   tip ;  verrucae 
alpha  large,  bearing  black  setae;  verrucae  beta 
and  rho  smaller,  with  white  setae.        Euschausia 
ii.  Labrum  rather  acutely  tho  not  deeply  notched  at 
tip;  verrucae  alpha  and  beta  not  of  contrasting 
colors, 
j.  Verrucae  beta  of  first  few  abdominal  segments 
nearly  directly  caudad  of  alpha;  verrucae  low, 
flat, 
k.  Setae  very  irregular  in  length,  some  as  long  as 
body  is  wide.  Hyphoraia 

kk.  Setae  sheared  off  even,  never  as  long  as  body 
is  wide. 

I.  Setae    of    thorax    black,  those    of    abdomen 

brown.  Phragmatobia 

II.  Setae  of  thorax  and  abdomen  brown. 

Lerina 
jj.  Verrucae  beta  of  first  few  abdominal  segments 
more  nearly  laterad  than  caudad  of  alpha ;  ver- 
rucae swollen. 


117] 


LEPIDOPTEROUS  LARVAE  — FRACKER 


117 


k.  Dorsum  bearing  conspicuous  transverse  yellow 
and  black  stripes;  verrucae  light  brown. 

Seirarctia 

kk.  Dorsum  not  bearing  transverse  stripes,  except 
sometimes  obscurely. 

I.  Verrucae  eta  of  abdomen  twice  as  broad  as 

verrucae  mu,  pear-shaped;  head  black  at 
least  in  part;  body  bearing  a  pale  lateral 
stripe;  setae  moderately  stiff.      Estigmene 

II.  Verrucae  eta  of  abdomen  elongate,  with  par- 

allel sides,  similar  to  verrucae   mu,  head 

usually  entirely  pale ;  no  lateral  stripe  of  a 

lighter  color  than  dorsum, 

m.  Setae  light   brown   or   gray,  unicolorous, 

rather  soft  like  fur.  Diacrisia 

mm.  Setae  either  very  dark  brown,  or  black, 

or  variegated  in  color,  always  stiff  like 

spines.  Arachnis 


The  following  species  were  examined; 


Utetheisa  hella 

A.  proxima  var.  autholea 

Boa  ampla 

A.  nevadensis  var.  superba 

Halisidota  maculata 

A.  phyllira 

H.  tessellaris 

A.  figurata 

H.  harrisii 

Apantesis  (cont'd) 

H.  cincUpes 

A.  nais 

H.  caryae 

A.  nais  var.  radians 

Ammalo  tenera 

A.  nais  var.  phalerata 

A.  eglenensis 

Hyphantria  cunea 

Euchaetias  egle 

H.  textor 

Hemihyalea  edwardsii 

Euhaphe  opella 

Eupseudosoma  involutum 

Haploa  clymene 

Ecpantheria  muzina 

H.  colona 

Isia  isahella 

H.  lecontei  var.  confinis 

Platyprepia  virginalis 

H.  confusa 

Arctia  caia  var.  americana 

H.  contiguus 

Ectypia  hivittata 

Leptarctia  calif ornica 

Apantesis  virgo 

Euschausia  ingens 

A.  virgo  var.  citrinaria 

E.  argentata 

A.  virguncula 

Hyphoraia  parthenos 

A.  michabo 

Phragmatohia  fuliginosa 

A.  anna  var.  persephone 

Lerina  incarnata 

A.  arge 

Seirarctia  echo 

118  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [118 

Estigmene  acraea  D.  latipennis 

E.  congma  Arachnis  zuni 
Diacrisia  rubra  A.  picta 

D.  virginica  A.  confusa  Dnice 

Family  Lithosiidae 

The  Lithosiidae  are  arctian  in  most  particulars  and  some  of  the 
larvae  are  said  to  be  indistinguishable  from  that  family.  When  ver- 
rueae  are  present,  those  of  the  last  two  thoracic  segments  are  out  of 
line  instead  of  being  in  definite  transverse  rows,  and  usually  only  one 
verruca  is  present  between  the  spiracle  and  the  proleg  in  addition  to 
the  single  seta  kappa.  Of  the  American  forms  the  writer  has  seen  only 
species  with  the  armature  reduced  to  single  setae  and  is  unable  to  de- 
scribe the  positions  of  the  verrucae  in  other  genera. 

The  arrangement  of  the  setae  is  similar  to  that  in  Noctuidae  except 
in  two  or  three  particulars.  The  Pi  group  on  the  mesothorax  and 
metathorax  is  bisetose  and  Rho  on  the  first  six  or  eight  abdominal  seg- 
ments is  bisetose.  An  additional  seta  is  also  present  near  mu  on  the 
abdominal  segments  but  the  Pi  group  consists  of  only  three  setae.  The 
crochets  are  homoideous.    The  labrum  is  shallowly  concave  at  tip. 

Hypoprepia  miniata.  The  three  setae  composing  the  Kappa  group 
on  the  mesothorax  placed  on  one  triple  chalaza,  equidistant  from  each 
other  and  arranged  in  a  horizontal  line. 

mice  nexa.  The  three  setae  composing  the  Kappa  group  on  the 
mesothorax  not  borne  on  the  same  chalaza,  theta  much  farther  eaudad 
than  kappa  and  eta,  which  are  close  together,  kappa  farther  ventrad 
than  the  others. 

Family  Syntomidae 

The  Syntomidae  are  differentiated  by  the  single  verruca  above 
that  of  the  kappa  group  on  the  last  two  thoracic  segments.  The  only 
other  similar  condition  is  in  one  genus  of  Pericopidae  but  the  position 
of  verruca  kappa  on  segment  7  serves  to  distinguish  the  latter  from  this 
family  (Figs.  67,  68). 

Head  similar  to  that  of  Arctiidae ;  front  almost  an  equilateral  tri- 
angle ;  labrum  moderately  acute  at  tip ;  secondary  setae  usually  present. 
Body  bearing  verrucae,  usually  well  developed.  Prothorax  with  verru- 
cae rho  rudimentary,  but  those  of  kappa  and  Pi  groups  large ;  mesotho- 
rax and  metathorax  with  all  setae  above  Kappa  group  forming  a  single 
verruca;  Pi  normal;  sigma  small  or  wanting.  Abdominal  segments  1 
to  8  (Figs.  67,  68)  with  alpha,  beta,  rho,  kappa,  eta,  and  mu  distinct 
and  separate  verrucae ;  kappa  often  small,  in  about  the  same  position 
on  segment  7  as  on  other  abdominal  segments ;  Pi  group  also  forming  a 


119]  LEPIDOPTEROUS  LARVAE  — FRACKER  119 

verruca  on  segments  1,  2,  7,  8,  and  9;  verrucae  alpha  often  contiguous 
on  abdomen;  secondary  setae  rare  or  absent.  Thoracic  legs  well  devel- 
oped ;  prolegs  normal  on  segments  3,  4,  5,  6,  reduced  or  wanting  on  10 ; 
crochets  uniordinal,  either  homoideous  or  heteroideous,  arranged  in  a 
mesoseries. 

Genera  of  Syntomidae: 

a.  Verrucae  reduced  in  size,  each  bearing  a  few  long  setae ;  head  bearing 
long  setae ;  prothoracic  legs  much  reduced.  Lycomorpha 

aa.  Verrucae  well  developed,  at  least  alpha,  beta,  and  rho  consisting  of 
very  numerous  setae. 
b.  Verrucae  kappa  and  eta  of  abdomen  both  well  developed  and  bear- 
ing numerous  setae. 
c.  Verrucae  kappa  of  segments  1  and  7  of  the  abdomen  bearing 
an  enlarged  group  of  clavate-plumed  setae,  tipped  with  black. 

Cosmosoma 
cc.  Verrucae  kappa  of  segments  1  and  7  normal. 

d.  Clypeus  emarginate  at  tip,  with  a  median  semicircular  con- 
cavity ;  front  white,  adfrontals  black ;  verrucae  alpha  of  first 
abdominal  segment  bearing  a  dark  brown  pencil,        Lymire 
dd.  Clypeus  not  emarginate  at  tip ;  front  coneolorous  with  ad- 
frontals; verrucae  alpha  of  segment  1  normal, 
e.  Secondary  setae  absent  on  front;  margins  of  front  strongly 
convex.  Eucereon 

ee.  Secondary  setae  of  front  rather  numerous ;  margins  of  front 
nearly  straight.  Ctenucha 

bb.  Verrucae  kappa  of  abdomen  abortive,  either  less  than  half  the 
size  of  verrucae  eta  or  both  rudimentary, 
c.  Verrucae  beta  of  segment  8  bearing  a  pencil  of  setae  at  least 
twice  as  long  as  those  of  verrucae  beta  on  preceding  segments. 

Syntomeida 
cc.  Verrucae  beta  on  segments  1  to  9  all  similar. 

d.  Verrucae  alpha  and  beta  of  abdomen  much  better  developed 

than  other  verrucae,  bearing  a  thick,  short  verricule  on  each 

segment.  Pseudomya 

dd.  Verrucae  alpha  and  beta  of  abdomen  similar  to  verrucae  rho 

and  kappa  and  those  of  the  thorax.  Scepsis 

The  following  species  were  examined: 
Lycomorpha  pholus  Syntomeida  epilais 

Cosmosoma  myrodora  Dyar  (1907)  S.  ipomeae 

Lymire  edwardsii  Pseudomya  minima 

Eucereon  conjine  Scepsis  fidvicollis 

Ctenucha  virginica  Syntomis  phegea  of  Europe 


120  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [120 

SUPERFAMILY    SATURNIOIDEA 

Workers  differ  as  to  the  number  of  families  into  which  this  group 
should  be  divided,  some  defining  the  Saturniidae  and  Ceratoeampidae, 
others  separating  Hemileuea  and  a  few  related  genera  from  the  former 
and  calling  them  Hemileucidae.  While  the  writer  recognizes  these  three 
families,  the  structure  of  the  larvae  compels  him  to  differ  from  previous 
workers  and  to  include  Automeris  and  Coloradia  in  the  Hemileucidae. 
The  necessity  for  this  change  will  be  shown  in  a  succeeding  paragraph. 
It  is  interesting  to  note  that  Miss  Edna  Mosher*  found  that  the  pupal 
characters  also  relate  Automeris  more  closely  to  the  Hemileucidae  than 
to  Samia  and  Saturnia.  Whether  specialists  will  later  find  that  the 
imagines  justify  this  arrangement  remains  to  be  seen. 

The  difference  is  emphasized  by  the  basis  of  separation  of  the 
Saturniidae  from  the  Ceratoeampidae.  Forbes  (1905),  following  Dyar, 
uses  for  this  purpose  the  scoli  beta  on  the  ninth  abdominal  segment, 
which  in  Ceratoeampidae  are  fused  on  the  dorsomeson.  He  seems  to  have 
overlooked  the  fact  that  such  a  fusion  also  occurs  in  Automeris  (Fig.  109) 
and  other  genera,  with  the  result  that  these  forms  trace  to  Cerat- 
oeampidae or  Hemileucidae  rather  than  to  Saturniidae. 

Five  types  of  arrangement  of  the  scoli  of  segments  8  and  9  are  found 
in  the  superfamily  and  four  of  them  are  shown  in  the  figures  of  Plate  X. 
In  all  five,  scoli  ?rho  and  Kappa  are  normal  on  segment  8,  and  two  similar 
but  more  dorsally  placed  scoli  of  doubtful  homology  are  found  on  9. 
Dorsad  of  these  four  are  found  the  following  modifications:  (a)  a  single 
mediodorsal  scolus  on  8,  none  on  9 ;  (b)  a  subdorsal  scolus  on  each  side 
on  8,  none  on  9;  (c)  a  mediodorsal  scolus  on  8,  and  also  one  on  9;  (d)  a 
mediodorsal  scolus  and  pair  of  adjacent  scoli  on  8  and  a  mesal  one  only 
on  9;  (e)  a  mediodorsal  scolus  on  9,  none  on  8.  The  Saturniidae  display 
either  (a)  (Fig.  108)  or  (b)  ;  the  Hemileucidae,  including  Automeris, 
are  armed  as  in  (c)  (Fig.  109)  ;  while  the  Ceratoeampidae  show  either 
(d)  (Fig.  110)  or  (e)  (Fig.  111).  It  is  to  be  noted  that  Hemileuea, 
Pseudohazis,  Automeris  and  Coloradia  are  more  similar  to  the  Cerato- 
eampidae in  the  armature  of  these  two  segments  than  to  the  Saturniidae. 

The  presence  of  scoli  (Figs.  73,  74)  distinguishes  this  superfamily 
from  all  others  except  Nymphalidae  and  Heliconiidae.  In  the  Saturni- 
oidea,  however,  the  head  is  never  tuberculate  nor  horned  and  is  always 
more  or  less  narrowed  dorsad ;  mediodorsal  scoli,  when  present,  are  con- 
fined to  segments  8  and  9.  The  few  difficult  cases  which  remain  are 
discussed  under  Nymphalidae.  The  position  and  number  of  the  scoli 
differ  so  greatly  that  an  extended  diagnosis  of  the  entire  group  on  that 


*The  Classification  of  the   Pupae  of  the   Ceratoeampidae  and   Hemileucidae. 
Ann.  Ent.  Soc.  Am.  7,  1914,  277-300. 


121]  LEPIDOPTEROUS  LARVAE  — FRACKER  121 

basis  is  impossible.  They  are  never  absent  in  American  species  so  far  as 
examined,  but  in  the  last  stage  of  the  European  Aglia  tau,  only  great 
dorsal  gibbosities  remain  to  show  that  the  recent  form  has  descended 
from  saturnian  ancestors. 

Beta  on  the  first  eight  abdominal  segments  of  members  of  this 
superfamily  is  either  represented  by  a  single  seta  or  is  wanting.  The 
eighth  segment  of  Ceratocampidae  is  an  exception,  for  here  there  is  a 
pair  of  small  scoli  caudad  of  the  large  mediodorsal  scolus  alpha. 

The  crochets  are  always  biordinal  and  arranged  in  a  mesoseries. 
(Fig.  106).  The  anal  prolegs  are  usually  flattened  laterocaudally  and, 
with  the  anal  plate,  form  a  triangular  pyramid. 

Families  of  Saturnioidea : 

a.  Ninth  abdominal  segment  not  bearing  a  scolus  on  the  dorsomeson; 

scoli  never  profusely  branched;  mediodorsal  scolus  of  segment  8, 

when  present,  never  associated  with  a  pair  of  smaller  scoli  latero- 

caudad  of  it  (Fig.  108).  SATURNIIDAE 

aa.  Ninth  abdominal  segment  bearing  a  scolus  on  the  dorsomeson  (Figs. 

109,  110,  111). 

b.  Scoli  alpha  of  mesothorax  scarcely  longer  than  abdominal  scoli; 

latter  often  profusely  branched ;  anal  plate  smooth. 

HEMILEUCIDAE 
bb.  Scoli  alpha   of  mesothorax   at  least  twice   as  long   as   scoli  of 
abdominal  segments  1  to  6;  scoli  never  profusely  branched; 
anal  plate  bearing  at  least  one  pair  of  small  chitinous  pro-       •  y 
cesses.  CERATOCAMPIDAE     ''MjuuryUd, 

Genera  of  Saturniidae: 

a.  Eighth  abdominal  segment  bearing  a  scolus  on  the  dorsomeson. 
b.  Scoli  alpha  of  mesothorax  and  metathorax  subequal  in  size  to  or 
smaller  than  other  body  scoli ;  scolus  Pi  never  present  on  abdom- 
inal segments  1  and  2. 
c.  Scoli  well  developed  and  conspicuous,  cylindrical,  higher  than 
wide.  Philosamia 

cc.  Scoli  reduced  to  small  knobs  not  higher  than  wide. 

d.  Labrum  notched  to  about  one-half  its  depth;  secondary  setae 

rare  or  absent  on  dorsum.  Rothschildia 

dd.  Labrum  notched  to  three-fourths  its  depth;  secondary  setae 

common  on  dorsum. 

e.  Abdominal  segments  1  to  7  each  bearing  a  transverse  yellow 

intersegmental  stripe;  scoli  Rho  and  Kappa  not  connected 

by  a  yellowish  ridge ;  spiracle  much  closer  to  scolus  Kappa 

than  to  Rho.  Tropea 


122  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [122 

ee.  Abdominal  segments  not  bearing  intersegmental  stripes  but 
seoli  Rho  and  Kappa  connected  by  a  yellowish  ridge ; 
spiracle  about  half  way  between  scoli  Rho  and  Kappa. 

Telea 

bb.  Scoli  alpha  of  mesothorax  and  metathorax  larger  than  those  of 

abdominal  segments  2  to  6. 

c.  Abdominal  segments  1  and  2  bearing  two  scoli  below  spiracle  ; 

scoli  alpha  of  first  abdominal  segment  much  larger  than  those 

of  second.  Samia 

cc.  Abdominal  segments  1  and  2  bearing  one  scolus  or  none  below 

spiracle,  or  sometimes  a  second  one,  very  rudimentary;  scoli 

alpha  of  first  abdominal  segment  not  much  larger  than  those 

of  second.  Callosamia 

aa.  Eighth  abdominal  segment  not  bearing  a  scolus  on  the  dorsomeson. 

b.  Secondary  setae  numerous  and  long,  obscuring  the  scoli,  which  are 

reduced.  Agapema 

bb.  Secondary  setae  rare  or  absent;  scoli  conspicuous,  subequal  in 

size  on  all  segments.  Saturnia 

Genera  of  Hemileucidae : 

a.  Lateral  spinules   of  supraspiracular   scoli   rho  usually   sparse,   not 
obscuring  axis  of  scolus;  head  smaller  than  prothorax;  secondary 
setae  often  Numerous ;  labrum  shallowly  notched. 
b.  Scoli  alpha  of  abdomen  modified  into  verricules  strikingly  different 
from  other  scoli. 
c.  Body  covered  with  small  white  dots,  each  dot  surrounding  the 
base  of  a  secondary  seta;  colors  variegated.  Hemileuca 

cc.  Body   not    covered    with    white    dots,    unicolorous    (except   in 
P.  hera).  Pseudohazis 

bb.  Scoli  alpha  of  abdomen  similar  to  those  of  other  parts  of  the 
body.  Coloradia 

aa.  Lateral  spinules  of  supraspiracular  scoli  Rho  long,  thickly  set,  ob- 
scuring axis  of  scolus ;  head  larger  than  prothorax ;  secondary  setae 
of  body  rare ;  labrum  notched  to  more  than  one-half  its  depth. 

Automeris 
Genera  of  Ceratocampidae : 

a.  Secondary  setae  numerous,  conspicuous,  and  distinctly  longer  than 
scoli  of  abdomen.  Basilona 

aa.  Secondary  setae  above  level  of  prolegs  inconspicuous. 

b.  Eighth  abdominal  segment  bearing  a  scolus   on   the   dorsomeson 

(Fig.  110)  ;  armature  of  metathorax  similar  to  that  of  mesothorax. 

c.  Prothorax  bearing  well  developed  scoli;  abdominal  scoli  slender, 

echinulate.  Citheronia 


123]  LEPIDOPTEROUS  LARVAE— FR ACKER  123 

cc,  Prothorax  bearing  rudimentary  seoli;  abdominal  scoli  broad  at 
base,  pointed,  smooth, 
d.  Seoli  of  abdominal  segments  1,  3,  and  5  one  fourth  as  long  as 
those  of  2,  4,  and  6 ;  those  of  segment  9  abortive. 

Adelocephala 

dd.  Seoli  of  abdominal  segments  1  to  6  uniform  in  size ;  those  of 

segment  9  conspicuous.  Syssphinx 

bb.  Eighth  abdominal  segment  without   a  scolus  on  the  dorsomeson 

(Fig.   111).  Anisota 

Philosamia  cynthia  is  the  only  American  species  of  its  genus.  The 
caterpillars  have  a  creamy  appearance  owing  to  a  powdery  bloom  which 
somewhat  obscures  the  blue  scoli. 

Bothschildia  jorulla  was  studied  but  B.  orizaba  has  not  been  seen. 

Tropea  luna,  when  the  caterpillar  is  fully  grown,  is  of  a  clear 
green  color  on  both  its  head  and  body.  On  the  caudal  margin  of  each  ab- 
dominal segment  there  is  a  transverse  yellow  line  and  another  on  either 
side  of  the  body  below  the  spiracles.  The  scoli  are  reddish  in  color 
and  rather  small  in  size. 

Telea  polyphemus  is  very  similar  to  Tropea  luna  except  in  the 
characters  given  in  the  key. 

Samia  cecropia  was  the  only  one  of  the  North  American  species  of 
this  genus  examined.  The  enlarged  dorsal  scoli  of  the  mesothorax,  meta- 
thorax,  and  first  abdominal  segment  distinguish  this  species  from  all 
other  members  of  the  family. 

Callosamia.  Two  species  of  this  genus  occur  in  the  eastern  states 
and  one  (C  calleta)  in  the  southwest,  Mexico  and  Arizona.  They  may 
be  distinguished  as  follows : 

a.  Scoli  of  first  eight  abdominal  segments  reduced  or  absent  in  last 

larval  instars. 

b.  Abdomen    bearing    a    distinct    longitudinal    subspiracular    yellow 

ridge.  C.  angulifera 

bb.  Abdomen  not  bearing  a  subspiracular  ridge.  C.  promethea 

aa.  Scoli  of  first  eight  abdominal  segments  conspicuous,  those  of  first 

segment  largest;  body  marked  with  black,  base  of  scoli  red. 

C.  calleta 

Agapema  anona  is  a  conspicuously  marked  yellow  and  black  species 
with  a  black  head.    A.  galbina  has  not  been  seen. 

The  three  species  of  Saturnia  examined  (pavonia-major,  pavonia- 
minor,  and  spini)  are  all  exotic.  The  larva  of  S.  mendocino  seems  not 
to  be  known  at  the  present  time. 

Hemileuca.    In  both  this  genus  and  Pseudohazis  the  scoli  alpha  of 


124  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [124 

the  last  two  thoracic  and  first  eight  abdominal  segments  are  modified 
into  verricules  or  thick  bunches  of  short  stiff  setae.  Other  scoli  are 
normal.  Three  species  (grotei,  juno,  and  tricolor)  have  not  been  seen. 
Pseudohazis  hera  is  included  in  the  following  synopsis  of  the  species  of 
Hemileuca  because  the  writer  was  unable  to  distinguish  between  speci- 
mens of  the  larvae  labeled  with  this  name  in  the  United  States  National 
Museum  and  those  of  H.  electra. 

a.  Verricules  alpha  of  mesothorax  each  surrounding  a   scolus  which 
arises  from  its  center  and  makes  the  verricule  conspicuously  differ- 
ent from  those  of  the  metathorax. 
b.  Secondary  setae  numerous,  about  half  as  long  as  scoli  and  often 
as  long  as  verricules.  H.  neumoegenii 

bb.  Secondary  setae  when  present  sparse  and  short. 

c.  Dorsal  abdominal  verricules  yeUow  or  light  brown,  always  lighter 
in  color  than  the  scoli. 
d.  Body  with  pale  areas  conspicuous,  more  extensive  than  dark 
areas.  H.  nevadensis 

dd.  Body  very  dark,  pale  areas  confined  to  minute  dots. 

H.  maia  var.  lucina 
cc.  Dorsal  abdominal  verricules  as  dark  in  color  as  the  scoli,  usually 
dark  brown  or  black,  at  least  at  tip.  H.  maia 

aa.  Verricules  of  mesothorax  similar  to  those  of  metathorax,  not  sur- 
rounding scoli. 
b.  Secondary  setae  numerous,  subequal  to  dorsal  verricules  in  length. 

H.  electra 
Pseudohazis  hera 
bb.  Secondary  setae  sparse,  much  shorter  than  verricules. 

H.  hualapai  var.  oliviae 

Pseudohazis.  Whatever  the  family  arrangement  in  Satumioidea, 
Pseudohazis  and  Hemileuca  must  be  placed  together  for  they  are  very 
similar.  The  difference  given  in  the  synopsis  is  not  a  good  one  (altho 
it  seems  to  hold  for  all  species  except  Pseudohazis  hera  of  the  north 
Pacific  states)  but  I  am  unable  to  improve  on  it  at  present.  P.  hera 
may  be  separated  from  the  other  species  by  the  numerous  white  dots  at 
the  bases  of  the  secondary  setae  and  is  thus  a  typical  Hemileuca.  In 
P.  eglanterina  most  of  the  setae  are  light  in  color  but  the  body  and 
verricules  are  a  dead  black.  The  verricules  of  P.  shastaensis  are  light 
in  color  at  base  and  tipped  with  black,  the  body  color  varying  in  different 
individuals. 

Automeris.  The  caterpillar  of  the  lo  moth  (A.  io)  is  well  known 
and  its  poisonous  spines  are  rather  notorious.  The  variety  fuscus  Lu- 
ther, also  found  in  the  Eastern  states,  has  the  scoli  much  smaller,  leav- 


125]  LEPIDOPTEROUS  LARVAE  — FR ACKER  125 

ing  a  great  part  of  each  segment  unprotected.     In  io  the  entire  body 
surface  seems  to  be  covered. 

Coloradia  pandora  was  seen  only  in  the  early  larval  stages,  when 
the  scoli  are  long  and  sparsely  branched.  These  may  possibly  become 
reduced  in  the  mature  larva.  Between  and  slightly  behind  scoli  Rho  and 
alpha  on  the  abdomen  is  a  single  seta,  beta. 

Basilona  imperialis.  The  larva  of  the  yellow  imperial  moth  is  well 
known;  the  long  setae  enable  it  to  be  identified  at  a  glance. 

atheroma.  The  caterpillar  of  C.  regalis  is  commonly  known  as  the 
''Hickory  Horned  Devil",  the  horns  being  the  subdorsal  scoli  of  the 
meso-  and  metathorax.  In  this  species  each  of  these  segments  is  armed 
with  a  pair  of  very  long  scoli  on  each  side  while  in  C.  sepulchralis  but 
one  long  scolus  is  found  on  each  side  on  each  of  the  two  segments;  in 
other  words  the  former  species  has  scoli  Rho  very  well  developed  on  the 
thorax,  while  in  the  latter  scolus  Rho  is  no  larger  than  Kappa  or  Pi. 

Adelocephala.  The  one  species  of  this  genus,  A.  bicolor,  is  very 
similar  to  Syssphinx  in  the  larval  stage,  but  the  reduced  armature  on 
each  alternate  abdominal  segment  and  the  echinulate  mesothoracic 
scoli  serve  to  separate  them. 

Syssphinx.  Peculiar  smooth  processes,  similar  to  the  thorns  of  a 
rose,  take  the  place  of  scoli  in  8.  heiligirodti,  the  only  species  I  have 
examined,  and  make  it  recognizable  at  a  glance.  Even  the  thoracic 
scoli  are  nearly  smooth.  As  the  genus  is  distinct  from  other  Saturnians 
in  adult  characters,  it  is  probable  that  these  processes  occur  in  the  other 
two  American  species,  ;S^.  hisecta  and  ;S^.  quadrilineata. 

Anisota.  While  the  species  of  Anisota  are  very  common,  their  small 
size  and  plain  appearance  have  caused  them  to  attract  less  attention 
than  their  relatives.  They  may  be  easily  distinguished  from  each  other 
as  foUows: 

a.  Scoli  alpha  of  abdominal  segments  1  to  6  very  much  reduced  and 
inconspicuous;  scoli  Kappa  well  developed;  caudal  projections  of 
suranal  plate  scarcely  longer  than  lateral  processes.      A.  ruhicimda 
aa.  Scoli  alpha  of  abdominal  segments  1  to  6  subequal  to  Kappa  in  size, 
b.  Scoli  alpha  of  abdominal  segments  1  to  6  much  shorter  than  thor- 
acic legs, 
e.  Caudal  projections  of  suranal  plate  distinctly  longer  than  wide, 
pointing  directly  caudad ;  body  with  conspicuous  black  longi- 
tudinal stripes,  not  dotted.  A.  senatoria 
cc.  Caudal  projections  of  suranal  plate  about  as  long  as  base  is 
wide,  pointing  caudodorsad ;  body  without  black  stripes  but 
covered  with  minute  dots.                                       A.  virginiensis 


126  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [126 

bb.  Seoli  alpha  of  abdominal  segments   1   to   6   conspicuous,   about 
as  long  as  thoracic  legs. 
c.  Body  uniformly  and  closely  tuberculate,  stripes  faint. 

A.  stigma 
cc.  Body  irregularly  and  rather  sparsely  tuberculate;  stripes  con- 
spicuous. A.  consularis 

Thauma  and  Hylesia.  No  specimens  of  these  genera  were  available 
for  study. 

SUPERFAMILY   SPHINGOIDEA 

The  Sphingidae,  the  only  members  of  this  superfamily,  include  some 
of  our  largest  caterpillars.  The  variation  in  structure,  while  not  great, 
is,  according  to  Forbes  (1911)  sufficient  to  enable  the  different  genera  to 
be  easily  identified.  His  synopsis  of  the  genera  and  discussion  of  the 
species  are  of  great  value  to  anyone  with  larvae  to  determine.  The  fam- 
ily characters  are  as  follows: 

Head  usually  smaller  than  prothorax,  usually  partially  retractile, 
shorter  in  dorsal  than  in  ventral  portion,  always  more  or  less  narrowed 
above;  head  in  Lapara  high  and  conical  above,  much  higher,  tho  no 
wider,  than  body;  setae  of  head  minute  and  numerous,  present  on  all 
parts  except  labrum  and  mouth  parts ;  front  reaching  less  than  half  the 
distance  to  vertical  triangle;  labrum  variously  notched.  Body  cylin- 
drical, plump;  secondary  setae  present  on  prolegs  but  rare  or  absent 
on  body;  primary  setae  reduced  or  wanting;  when  present,  kappa  and 
eta  distant,  eta  farther  dorsad  than  kappa  and  almost  as  high  as  spira- 
cle ;  segment  8  bearing  a  slender  horn  in  most  genera ;  when  reduced,  a 
scar  or  corniculum  marks  its  location  except  in  Lapara.  Prolegs  present 
and  large,  set  close  together,  bearing  biordinal  crochets  arranged  in  a 
mesoseries.  Anal  prolegs  flattened  laterad,  forming,  with  the  suranal 
plate,  a  triangular  pyramid. 


RHOPALOCERA 

The  butterflies  seem  to  have  been  separated  from  other  Lepidop- 
tera  at  a  very  remote  period.  They  have  been  specialized  in  all  stages 
along  entirely  different  lines.  The  larvae  seem  to  have  separated  from 
the  Microlepidoptera  before  the  time  when  kappa  and  eta  became  adja- 
cent on  the  abdomen. 

Scudder's  "Butterflies  of  the  Eastern  United  States  and  Canada" 
is  at  present  the  authority  on  all  stages  of  Rhopalocera.  So  many  ento- 
mologists have  no  access  to  a  copy  of  this  beautiful  but  expensive  work, 
however,  that  it  is  considered  worth  while  to  cover  the  group  so  far  as 


127]  LEPIDOPTEROUS  LARVAE— FRACKER  127 

possible  here.  Many  of  the  characters  are  adapted  from  his  descrip- 
tions and  a  free  use  has  been  made  of  his  method  of  separating  the 
genera. 

On  the  basis  of  larval  structure  the  butterflies  may  be  divided  into 
about  five  groups.  In  the  Hesperioidea,  including  the  Hesperiidae  and 
Megathymidae,  the  crochets  are  triordinal  and  arranged  in  a  complete 
circle,  and  the  body  bears  very  short  numerous  secondary  setae  but  no 
other  form  of  armature;  The  larvae  of  the  Lycaenoidea  (the  Lycaenidae 
and  Eriodinidae)  are  somewhat  onisciform  in  shape,  the  head  small  and 
retractile,  the  body  covered  with  coarse  secondary  setae.  Forbes  has 
called  attention  to  the  peculiar  form  of  the  prolegs,  which  bear  an  in- 
terrupted mesoseries  of  crochets  with  a  spatulate  fleshy  lobe  arising 
near  the  interruption.  The  Papilionidae  and  Parnassiidae  are  charac- 
terized by  the  presence  of  prothoracic  osmateria ;  in  the  former  the  body 
is  practically  without  setae,  but  both  secondary  setae  and  verrucae  are 
present  in  the  latter.  The  Pieridae  are  considered  by  many  as  belonging 
to  the  Papilionoidea  but  the  larvae  are  not  closely  related.  All  the 
remaining  families,  Libytheidae,  Lymnadidae,  Ithomiidae,  Heliconiidae, 
Agapetidae,  and  Nymphalidae,  may  be  grouped  together  as  Nymphaloi- 
dea,  altho  they  have  few  larval  structures  in  common.  They  are  all 
armed  with  scoli  or  fleshy  filaments  or  a  bifurcate  suranal  plate,  except 
the  Libytheidae,  which  are  distinguished  from  the  others  by  the  pseudo- 
circular  arrangement  of  the  crochets. 

Family  Hesperiidae 

The  conspicuous  structure  of  the  larvae  of  skippers  is  the  large  head 
attached  to  a  strongly  constricted  "collar".  This  head  is  covered  with 
numerous  secondary  setae,  often  plumose  but  never  long,  sometimes 
borne  on  chalazae.  The  labrum  is  shallowly  concave  at  tip  and  usually 
a  shallow  mesal  groove  is  present  on  the  cephalic  surface.  The  front 
extends  about  two-thirds  of  the  distance  to  the  top  of  the  head. 

The  body  is  either  cylindrical  or  fusiform,  widest  at  the  proleg- 
bearing  segments,  usually  tapering  considerably  toward  each  end;  sec- 
ondary setae  numerous,  often  very  short;  small  flattened  plates  some- 
times present,  possibly  showing  position  of  primary  setae;  segments 
divided  into  indistinct  annulets,  incisions  all  shallow  or  obscure;  pro- 
thoracic  shield  narrow,  often  indistinct.  Prolegs  with  triordinal  crochets 
in  a  complete  circle. 

Scudder  divides  the  family  into  Hesperidi  and  Pamphilidi  and 
gives  a  table  for  the  separation  of  the  genera  of  the  former  group  in 
all  stages.  The  family  is  so  poorly  represented  at  the  National  Museum 
that  at  present  nothing  can  be  added  to  his  work. 


128  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [128 

Family  ]^lEGATHTMroAE 

'  No  species  of  this  small  family  is  found  east  of  the  Rocky  Mountains 
and  even  there  the  boring  habit  of  the  larvae  makes  their  discovery 
difficult.  Three  specimens  of  Megathymus  yuccae  have  been  examined 
and  the  following  characters  are  taken  from  them. 

Head  rounded,  about  as  high  as  wide,  rugose,  partially  retractile, 
smaller  than  prothorax;  front  triangular,  sides  almost  straight,  reach- 
ing about  half  way  to  top  of  head;  labrum  with  a  small,  acute,  mesal 
notch;  setae  very  much  reduced;  ocelli  small,  inconspicuous.  Protho- 
racic  shield  narrow,  sometimes  indistinct;  setae  of  body  much  reduced, 
apparently  wanting  on  its  dorsal  half,  numerous  and  short  on  ventral 
half  of  first  two  thoracic  segments,  rare  or  absent  on  abdomen,  except 
on  prolegs.  Thoracic  legs  well  developed,  bearing  numerous  setae  on 
their  caudomesal  surfaces;  prolegs  short,  bearing  a  complete  ellipse  of 
biordinal  crochets,  series  sometimes  slightly  broken  at  mesal  and  lateral 
ends;  spiracles  large,  those  of  segment  8  placed  somewhat  farther  dor- 
sad than  the  others. 

Family  Lycaenidae 

Head  from  one-sixth  to  one-half  as  wide  as  body,  usually  deeply 
retractile,  often  overhung  by  the  prothorax;  front  broad,  often  extend- 
ing over  half  way  to  vertical  triangle ;  labrum  various.  Body  depressed, 
widest  above  prolegs,  usually  tapering  strongly  toward  the  ends;  sec- 
ondary setae  numerous,  sometimes  in  tufts  and  pencils,  usually  coarse 
and  short.  This  form  of  body  does  not  occur  elsewhere  in  Lepidoptera 
except  in  the  Zygaenoidea.  Prolegs  with  a  mesoseries  of  triordinal  cro- 
chets well  developed  at  the  ends  of  the  series,  shorter  or  interrupted  at 
the  middle,  and  with  a  spatulate  or  clavate  fleshy  lobe  arising  near  the 
interruption  (Fig.  79). 

From  the  very  meager  material  at  hand,  the  following  synopsis 
has  been  prepared.    It  follows  to  some  extent  that  of  Scudder : 

a.  Head  at  least  one-third  the  diameter  of  the  body, 
b.  Head  about  one-half  the  diameter  of  the  body. 

e.  Verrucae  large  and  distinct,  with  short  setae.  Eumaeus 

cc.  Verrucae  inconspicuous  or  absent,  setae  long,  arranged  in  trans- 
verse groups.  Feniseca 
bb.  Head  about  one-third  the  diameter  of  the  body, 
c.  Lateral  line  continuous  and  rather  conspicuous. 

d.  Prothorax  longer  and  higher  than  mesothorax;  abdomen 
marked  by  a  pair  of  subdorsal  lines  between  mediodorsal  and 
lateral  lines.  Mitoura 


129]  LEPIDOPTEROUS  LARVAE  — FRACKER  129 

dd.  Prothorax  much  smaller  than  mesothorax;  abdomen  usually 
not  marked  by  subdorsal  lines.  Thecla 

ec.  Lateral  line  discontinuous  and  faint  or  absent. 

d.  Labrum  notched  to  about  one-third  its  depth.      Chrysophanus 
dd.  Labrum  very  shallowly  concave  at  tip. 

e.  Body  widest  in  metathoracic  region,  tapering  rapidly  cepha- 
lad  and  gradually  caudad. 
f.  Fifth  ocellus  located  below  center  of  arc  formed  by  first 
four  ocelli;  second  ocellus  out  of  line,  making  arc  un- 
even. Calycopys 
ff.  Fifth  ocellus  located  at  center  of  arc  formed  by  first  four 
ocelli ;  arc  regular,  even.  Heodes 
ee.  Body  widest  in  region  of  segment  6  of  abdomen,  tapering 
gradually  cephalad  and  rapidly  caudad.                 Uranotes 
aa.  Head  less  than  one-fourth  the  diameter  of  the  body. 

b.  Body  marked  by  longer  setae  on  outer  margin  of  narrow  dorsal 
area  than  on  other  parts, 
c.  Anal  segment  broad  and  greatly  depressed.  Everes 

Philotes 
cc.  Anal  segment  narrow  and  moderately  depressed.  Cyaniris 

bb.  Body  covered  with  setae  of  uniform  length  throughout. 

c.  Setae  of  body  long,  closely  set;  vertical  triangle  rather  broad. 

Nomiades 
cc.  Setae  of  body  short,  rather  sparse;  vertical  triangle  very  nar- 
row. Rusticus 

This  synopsis  was  prepared  to  cover  the  following  species.     All 
were  examined  in  the  National  Museum  except  those  marked  with  an 
asterisk  and  they  are  carefully  described  by  Scudder : 
Eumaeus  atala  Chrysophanus  thoe 

Feniseca  tarquinius  Calycopys  cecrops 

Mitoura  damon  Heodes  hypophleas  ^ 

Thecla  adenostomatis  Uranotes  melinus 

T.  edwardsii  Everes  comyntas 

T.  liparops  Philotes  sonorensis 

T.  calanus  Cyaniris  laden  (pseudargiolus) 

T.  acadica  Nomiades  couperii* 

T.  spini  of  Europe  Rusticus  melissa 

R.  scudderii* 

Family  Riodinidae 

No  riodinid  larvae  have  been  seen.  The  group  is  sometimes  called 
a  subfamily  of  Lycaenidae  to  which  it  is  closely  related.  The  head  is 
said  to  be  about  half  the  diameter  of  the  subonisciform  body.     In  the 


130  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [130 

absence  of  material  it  is  impossible  to  be  sure  that  the  prolegs  and  cro- 
chets are  of  the  peculiar  form  seen  in  Lycaenidae. 

Family  Libytheidae 

American  larvae  of  this  family  are  not  known  to  me,  but  the  follow- 
ing characters,  for  which  Edwards  is  the  authority,  are  duplicated  in 
Libythea  celtis  of  Europe. 

Hypatus  hachmani.  Body  cylindrical,  somewhat  thickened  in  re- 
gion of  last  two  thoracic  segments;  dorsum  of  last  two  abdominal  seg- 
ments curved  abruptly  ventrad;  each  segment  divided  into  four  or  five 
annulets ;  numerous  secondary  setae  present,  a  group  at  the  base  of  each 
leg  and  one  on  the  first  annulet  of  each  segment,  borne  on  chalazae. 

In  addition,  L.  celtis  has  the  head  covered  with  secondary  setae, 
the  second,  third,  and  fourth  ocelli  on  papillae,  the  other  ocelli  reduced, 
and  the  crochets  arranged  in  a  pseudocircle.  The  labrum  is  shallowly 
concave  at  tip.  The  general  structure  and  habits  are  similar  to  those 
of  the  Pieridae,  but  the  presence  of  the  lateral  rudimentary  crochets  of 
the  pseudocircle  will  distinguish  them. 

The  larva  of  Hypatus  carinenta  seems  to  be  unknown. 

Family  Lymnadidae 

Head  about, as  large  as  prothorax,  bilobed;  labrum  with  a  rounded 
emargination.  Body  bearing  fleshy  filaments  in  the  subdorsal  region 
(Fig.  92),  at  least  on  the  mesothorax;  not  more  than  three  pairs  of  these 
processes  present  in  American  species;  coloration  always  consisting  of 
transverse  black  and  green  stripes. 

Anosia  plexippus  bears  a  pair  of  these  filaments  on  the  mesothorax 
and  another  pair  on  the  eighth  abdominal  segment.  There  are  three 
transverse  black  stripes  on  each  segment.  A.  berenice  bears  filaments 
on  the  mesothorax  and  the  second  and  eighth  abdominal  segments.  The 
middle  of  each  segment  bears  a  wide  double  broken  black  band  reaching 
over  the  dorsum  to  the  end  of  each  proleg. 

Lycorea  cleobaea  is  the  only  species  of  Lycorea  north  of  Mexico. 
No  specimens  of  the  larvae  are  in  the  National  Museum;  but  a  related 
species,  L.  atergatis  of  southern  Mexico,  has  fleshy  filaments  on  the 
mesothorax  only,  and  the  black  color  on  the  abdomen  covers  the  venter 
and  the  intersegmental  incisions. 

Family  Ithomhdae 

The  larvae  of  the  three  North  American  species  of  these  Nymphal- 
oidea  seem  to  be  unknown.  "Wilhelm  Miiller  (1886)  describes  in  a  brief 
way  other  species  of  the  same  genera  but  gives  no  very  definite  structu- 
ral data.     The  only  distinguishing  characters  mentioned  are  arrange- 


131]  LEPIDOPTEROUS  LARVAE  — FRACKER  131 

ments  of  the  setae  in  the  first  larval  instar.  In  later  stages  numerous 
secondary  setae  are  present  and  sometimes  small  cornicula  (''zipfel") 
below  the  spiracle,  but  no  other  form  of  armature. 

Family  Heliconiidae 

But  one  species  of  this  large  tropical  group  ranges  into  the  United 
States.  The  larvae  are  all  typical  Nymphalidae  in  most  particulars. 
The  characters  given  are  drawn  from  Apostraphia  charithonia  of  Flor- 
ida but  they  apply  also  to  most  of  the  known  South  American  forms. 

Head  distinctly  bilobed,  bearing  a  long,  slender  scolus  on  each  lobe ; 
front  not  reaching  half  way  to  top  of  head ;  color  green  with  ocelli 
located  on  a  black  spot  and  another  pair  of  black  spots  on  the  epicra- 
nium  near  the  union  of  the  arms  of  the  epicranial  suture. 

Prothorax  smaller  than  head,  bearing  a  dorsal  shield;  shield  with 
one  large  seta  but  no  scoli;  mesothorax  and  metathorax  each  bearing 
a  subdorsal  pair  of  scoli  and  one  on  each  side  slightly  above  the  spiracu- 
lar  level ;  no  subspiraeular  scoli  present  on  thorax,  but  several  verrucae 
located  at  the  base  of  each  leg.  Abdomen  with  three  scoli  present  on 
each  side  on  each  segment,  one  subdorsal,  one  supraspiracular,  and  one 
subspiraeular;  no  scoli  on  dorsomeson;  small  chalaza  or  scolus  present 
on  abdominal  segments  1,  2,  7,  and  8,  in  line  with  prolegs  in  the  position 
of  the  Pi  group  and  another  very  small  one  in  the  position  of  sigma; 
scoli  all  very  long  and  slender,  nearly  as  long  as  body  is  wide ;  secondary 
setae  minute  or  absent  above  level  of  prolegs,  small  on  ventral  surface. 
Prolegs  all  present  and  well  developed ;  crochets  biordinal  or  triordinal, 
arranged  in  a  mesoseries. 

The  above  description  applies  equally  well  in  almost  every  particu- 
lar to  Agraulis  of  the  Nymphalidae,  but  in  that  genus  the  scoli  are  not 
quite  so  long  and  slender.  The  shape  of  the  head  offers  the  most  con- 
venient means  of  differentiating  the  two  genera,  altho  the  difference 
is  hard  to  describe.  In  the  Heliconiidae  the  head  scoli  are  located  back 
of  the  plane  of  the  front  and  are  not  borne  on  conical  projections  of 
the  head.  The  scoli  of  Agraulis  are  borne  on  prominent  conical  pro- 
jections which  gradually  merge  into  the  scoli  and  which  extend  ceph- 
alodorsad  so  that  the  bases  of  the  scoli  are  somewhat  cephalad  of  the 
plane  of  the  front. 

Family  Agapetidae 

The  larvae  of  the  satyrs  differ  from  other  Nymphaloidea  in  several 
particulars  and  their  external  characters  do  not  indicate  a  very  close 
relationship.  All  their  relatives  except  Anaea  and  Hypatus  have  an 
external  armature  consisting  of  scoli  or  fleshy  filaments.  On  the  other 
hand  none  but  the  Agapetidae  have  a  bifurcate  suranal  plate. 


132  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [132 

Head  as  large  as,  or  larger  than,  prothorax,  which  usually  forms  a 
constricted  neck;  surface  rugose  or  tuberculated ;  shape  varying  from 
rounded  above  to  bilobed  or  horned ;  labrum  usually  deeply  emarginate ; 
ocelli  in  most  or  all  species  with  the  third  ocellus  borne  on  an  elevated 
tubercle  and  very  much  larger  than  the  others.  Body  with  numerous, 
well  developed,  lenticle-like  papillae  bearing  small  secondary  setae;  seg- 
ments divided  into  annulets  usually  six  in  number;  suranal  plate  bifur- 
cate, bearing  a  pair  of  very  rugose  conical  projections  (Fig.  84).  Pro- 
legs  bearing  a  mesoseries  of  uniordinal,  biordinal,  or  triordinal  crochets. 

Grenera  of  Agapetidae : 

a.  Head  rounded  above,  not  bearing  conspicuous  scoli,  not  with  latero- 
dorsal  angles. 
b.  Caudal  processes  widely  separated,  as  far  apart  as  long,  parallel 
(Fig.  84).  Cercyonis 

bb.  Caudal  processes  almost  contiguous  at  base,  divergent. 

c.  Mediodorsal  and  lateral  stripes  conspicuous.  Oeneis 

cc.  Mediodorsal  and  lateral  stripes  indistinct.  Coenonympha 

aa.  Head  bearing  a  pair  of  conspicuous  dorsal  prominences,  sometimes 
reduced  to  sharp  laterodorsal  angles. 
b.  Dorsal  prominence  about  as  long  as  head  is  wide. 

c.  Head,  including  prominences,  about  once  and  a  half  as  high  as 
wide,      '  Enodia 

cc.  Head,  including  prominences,  about  twice  as  high  as  wide. 

Satyrodes 
bb.  Dorsal  prominences  reduced  to  low  knobs. 

c.  Larger  papillae  of  head  few  and  sparse.  Neonympha 

cc.  Larger  papillae  of  head  closely  placed.  Cissia 

The  discussion  and  key  are  based  on  the  following  species;  those 
not  seen  by  the  writer  but  described  by  Scudder  are  marked  with  an 
asterisk  (*)  : 

Cercyonis  meadii,  C.  alope* 
Oeneis  chryxus,  0.  jutta*  0.  noma 
Coenonympha  typhon,  C.  elko 
Enodia  portlandia 
Satyrodes  canthus* 
Neonympha  phocion* 
Cissia  eurytus*  C.  sosyiius* 

Family  Nymphalidae 

Even  when  limited  by  the  removal  of  the  other  Nymphaloidea,  this 
family  is  a  large  and  varied  group.  Scudder  divides  it  into  five  tribes 
which  are  distinct  in  all  stages;  and  these  tribes  are  retained  here  as 


133]  LEPIDOPTEROUS  LARVAE  — FR ACKER  133 

subfamilies.  All  of  these  species  possess  seoli,  either  on  the  head  or 
body,  except  some  of  the  Apaturinae,  especially  Anaea.  This  distin- 
guishes them  from  all  other  butterfly  larvae. 

The  separation  from  the  Saturnioidea  is  more  difficult.  The  ar- 
rangement of  the  scoli  is  apparently  the  same  in  the  two  families  but  is 
modified  in  different  ways.  In  no  nymphalids  are  mediodorsal  scoli 
limited  to  segments  8  and  9  when  they  are  present  at  all.  The  genera 
in  which  they  are  absent  from  the  dorsomeson  and  in  which  the  head 
scoli  are  also  absent  are  Euptoieta,  Speyeria  and  Anaea.  The  first  is 
made  conspicuous  by  the  great  development  of  the  subdorsal  scoli  on 
the  prothorax,  and  the  last  by  the  very  large  head ;  but  no  way  of  sep- 
arating the  species  of  Speyeria  from  those  of  Saturnia  is  known  to  me. 
Unfortunately  no  specimens  of  Speyeria  have  been  available  and  I  am 
compelled  to  rely  upon  Edwards'  description.  It  is  probable  that  the 
head  of  the  saturnian  is  much  smaller,  that  the  crochets  are  more  regu- 
larly biordinal,  and  that  the  anal  prolegs  are  much  larger  than  in 
Speyeria. 

The  work  of  Wilhelm  Miiller  (1886)  on  this  family  is  a  classic.  It  is 
particularly  notable  as  being  the  earliest  scientific  study  of  all  the  stages 
of  the  larvae  of  any  group.  His  demonstration  of  the  fact  that  the  scoli 
have  no  relation  to  the  primary  setae  is  conclusive  and  is  the  reason 
for  the  omission  here  of  the  nomenclature  used  in  other  parts  of  the 
paper.  Instead,  terms  are  used  denoting  position,  especially  the  follow- 
ing: mediodorsal,  subdorsal,  supraspiracular,  subspiracular,  and  sub- 
ventral.  Their  meaning  is  obvious  and  they  answer  as  well  as  symbols 
in  cases  where  there  is  but  one  transverse  row  of  scoli,  or  other  form  of 
armature,  to  t&e  segment,  as  in  this  group. 

Subfamilies  of  Nymphalidae: 

a.  Scoli  always  present,  usually  subequal  in  size,  never  five  times  as 
long  on  mesothorax  as  on  abdominal  segments  1,  3,  5,  and  6. 
b.  Mediodorsal  scoli  never  present  on  abdominal  segments ;  head  rarely 
bearing  numerous  secondary  setae.  Argynninae 

bb.  Mediodorsal  scoli  present  on  at  least  a  few  abdominal  segments; 
head  usually  bearing  numerous  secondary  setae. 
c.  Abdomen  bearing  a  pair  of  scoli  at  base  of  each  proleg  similar 
to  dorsal  scoli  in  shape,  but  smaller;  lateral  setae  of  all  scoli 
slender,  closely  placed;  two  mediodorsal  scoli  on  segment  8  or 
one  each  on  segments  8  and  9.  Melitaeinae 

cc.  Abdomen  bearing  a  single  scolus  or  none  at  the  base  of  each 
proleg;  when  present,  shorter  than  other  scoli;  lateral  setae  of 
dorsal  scoli  stout,  sparse  (Fig.  74) ;  only  one  mediodorsal  sco- 
lus on  segment  8,  none  on  segment  9  (Fig.  112).      Vanessinae 


134  ILUNOIS  BIOLOGICAL  MONOGRAPHS  [134 

aa.  Seoli  often  wanting,  when  present  ten  times  as  long  on  mesothorax 
as  on  abdominal  segments  1,  3,  5  or  6. 
b.  Mesothorax  bearing  seoli  about  as  long  as  body  is  wide. 

Nymphalinae 
bb.  Mesothorax  without  seoU.  Apaturinae 

Genera  of  Argynninae: 

a.  Abdominal  seoli  over  half  as  long  as  segments. 

b.  Subdorsal  prothoracie  seoli  twice  as  long  as  those  of  abdomen, 
clavate ;  head  bigibbous,  rounded.  Euptoieta 

bb.  Subdorsal  prothoracie  seoli  smaller  than  those  of  abdomen,  not 
clavate. 
c.  Head  armed  above  with  long  seoli  or  short,  pointed  prominences ; 
abdominal  seoli  not  longer  than  those  of  thorax. 
d.  Seoli  of  head  long,  spine-like ;   subdorsal  pair   of  prothorax 
rudimentary-.  Agraulis 

dd.  Seoli  of  head  short,  not  spine-like ;  subdorsal  pair  of  protho- 
rax about  as  long  as  those  of  abdomen.  Argynnis 
cc.  Head  rounded  above,  bigibbous,  not  armed  with  seoli  or  pointed 
prominences ;  abdominal  seoli  longer  than  those  of  thorax. 

Speyeria 
aa.  Abdominal  seoli  less  than  half  as  long  as  segments;  head  rounded, 
bigibbous;  prothoracie  seoli  sometimes  long.  Brenthis 

Grenera  of  Melitaeinae: 

a.  Subspiracular  seoli  present  on  aU  three  thoracic  segments. 

b.  Mediodorsal  seoli  light  in  color,  others  black ;  body  with  numerous 

slender  secondary  setae.  Lemonias 

bb.  Mediodorsal  seoli  black,  like  the  others;  body  with  stout,  sparse 

secondary  setae.  Euphydryas 

aa.  Subspiracular  scolus  present  on  mesothorax  but  absent  or  reduced 

to  a  single  seta  on  metathorax. 

b.  Dorsal  seoli  stout,  sometimes  verruca-like,  about  twice  as  high  as 

broad.  Phyciodes 

bb.  Dorsal  seoli  slender,  at  least  three  times  as  high  as  broad. 

c.  Dorsal  abdominal  seoli  not   as  long  as  segments,   subequal   in 
length  to  those  of  metathorax. 
d.  Dorsal  seoli  of  mesothorax  and  metathorax  subequal  in  size; 
body  striped,  not  spotted, 
e.  Supraspiracular    scolus    of    segment    8    dorsad    and    only 
slightly  cephalad  of  spiracle ;  body  with  conspicuous  trans- 
verse stripes.  Cinclidia 
ee.  Supraspiracular  scolus  of  segment  8  cephalad  of  top  of 


135]  LEPIDOPTEROUS  LARVAE  — FR ACKER  135 

spiracle,     much    farther    cephalad    than    subspiracular ; 
stripes  longitudinal.  Charidryas 

dd.  Dorsal  scoli  of  mesothorax  at  least  one  and  a  half  times  as 
long  as  those  of  metathorax;  body  closely  spotted;  each  seg- 
ment bearing  a  large  red  dorsal  macula.  Chlosyne 
cc.  Dorsal  abdominal  scoli  much  shorter  than  those  of  mesothorax 
and  metathorax;  supraspiracular  scolus  of  abdominal  segment 
8  dorsad  of  spiracle;  stripes  longitudinal.                    Thessalia 
Genera  of  Vanessinae: 

a.  Head  bearing  a  pair  of  dorsal  scoli. 
b.  Spinules  of  body  scoli  erect;  subapical  ones  in  a  whorl  (Fig.  74). 
c.  Mediodorsal  scoli  present  on  all  abdominal  segments;  head  scoli 
no  higher  than  head  is  wide.  Polygonia 

cc.  Mediodorsal  scoli  present  only  on  abdominal  segments  7  and  8; 
head  scoli  twice  as  high  as  head  is  wide.  Mestra 

bb.  Spinules  of  body  scoli  appressed,  not  arranged  in  a  whorl;  head 
scoli  not  clavate. 
c.  Dorsal  scoli  of  head  low,  strongly  tapering,  concolorous  with  head, 
indefinite  at  base;  body  scoli  needle-like,  with  two  or  three 
principal  spinules.  •  Eugonia 

cc.  Dorsal  scoli  of  head  cylindrical,  distinct  at  base,  darker  than 
dorsal  part  of  head ;  body  scoli  cylindrical,  rather  stout,  with 
numerous  lateral  spinules.  Junonia 

aa.  Head  rounded  above,  bigibbous,  bearing  chalazae  but  no  scoli. 
b.  Mediodorsal  scolus  absent  on  abdominal  segments  1  and  2,  present 
on  segments  4  to  8,  usually  also  on  segment  3.  Euvanessa 

bb.  Mediodorsal  scoli  present  on  abdominal  segment  2. 
c.  Mediodorsal  scoli  present  on  segments  1  to  8  inclusive. 

Vanessa 
cc.  Mediodorsal  scolus  absent  from  segment  1.  Aglais 

Genera  of  Nymphalinae : 

a.  Abdominal  segments  3  and  8  bearing  scoli  as  long  as  those  of  meso- 
thorax. Limeniiis 

aa.  Abdominal  segments  3  and  8  without  scoli  or  with  small  ones. 

Basilarchia 
Genera  of  Apaturinae : 

a.  Head  crowned  by  a  pair  of  scoli ;  suranal  plate  bifurcate.    Chlorippe 
aa.  Head  crowned  only  by  a  few  low  tubercles;  suranal  plate  entire. 

Anaea 
The  following  species  of  the  Nymphalidae  have  been  examined  by 


136  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [136 

the  writer  and  on  them  the  preceding  synopsis  is  based. 
Argynninae  Vanessinae  (continued) 

Euptoieta  claudia  Mestra  amymone 

Agraulis  vanillae  Eugonia  calif ornica 

Argynnis  cyhele  Junonia  coenia 

Melitaeinae  Euvanessa  antiopa 

Lemonias  chalcedon  Vanessa  atalanta 

L.  macglashani  V.  huntera 

L.  iaroni  V.  cardui 

L.  editha  V.  caryae 

Euphydryas  phaetan  Aglais  mUherti 

Phyciodes  montana  Nymphalinae 

Cinclidia  harrisii  Limenitis  hredowii  var.  cali- 

Charidryas  nycteis  f ornica 

C.  ismeria  BasUarchia  archippus 

Chlosyne  lacinia  B.  astyanax 

Thessalia  leanira  Apaturinae 

Yanessinae  Chlorippe  clyton  • 

Polygonia  interrogationis  C.  alicia 

P.  satyrus  C.  celtis 

P.  zephyrus  Anaea  andria 

P.  comma 
Scudder  has  described  and  figured  the  following  in  addition  to 
some  of  the   above  and  their  place   in  the  synopsis  is  based  on  his 
descriptions. 

Argynninae 

Argynnis  aphrodite 

A.  atlantis 
Speyeria  idalia 
Brenthis  myrina 

B.  montinus 
B.  bellona 

Family  Piebidae 

Altho  closely  related  to  Papilionidae,  the  larvae  of  Pieridae  are  of 
a  generalized  structure  little  resembling  their  more  advanced  relatives. 
They  seem  to  be  characterized  principally  by  a  lack  of  osmateria,  fleshy 
filaments,  cephalic  or  anal  horns,  or  special  developments  of  the  prolegs. 
Chalazae,  the  only  form  of  armature  present,  make  some  of  the  secon- 
dary setae  much  more  conspicuous  than  others.  The  conspicuous  setae 
are  not  the  "primary"  ones,  as  Forbes  seems  to  have  assumed;  they  are 
too  numerous  and  not  in  the  right  locations. 


137]  LEPIDOPTEROUS  LARVAE— FR ACKER  137 

Head  about  as  large  as  prothorax,  not  retractile  except  in  Phoehis, 
distinct  from  prothorax  and  with  caudal  half  well  developed;  front 
extending  about  half  way  to  top  of  head ;  labrum  moderately  emarginate ; 
numerous  secondary  setae  present,  varying  from  minute  to  large  and 
borne  on  papillae  of  various  sizes ;  surface  of  head  varying  from  nearly 
smooth  to  rugose  and  irregular.  Body  bearing  numerous  secondary 
setae,  sometimes  all  similar,  usually  of  widely  different  sizes  and  borne 
on  chalazae  varying  from  microscopic  to  conspicuous;  segments  divided 
into  annulets,  usually  six  in  number,  each  annulet  bearing  either  a 
single  row  of  setae  or  a  band  nearly  its  full  width.  Prolegs  present  on 
segments  3,  4,  5,  6,  and  10,  all  similar  in  size;  crochets  biordinal  or 
triordinal,  always  arranged  in  a  mesoseries. 

The  following  synopsis  includes  six  of  the  nine  genera  occurring 
north  of  Florida  and  east  of  Texas  and  the  Rocky  Mountains.  No 
specimens  of  Nathalis  iole,  Zerene  caesonia,  or  Pyrisita  mexicana  of  the 
southern  states  have  been  available.  Larvae  of  all  of  the  northern 
species  east  of  the  Rockies  have  been  examined  except  Eurymus  interior. 

Genera  of  Pieridae: 

a.  Setae  of  head  borne  on  chalazae,  those  of  front  much  smaller  than 
those  laterad  of  the  epicranial  suture. 
b.  Head  with  many  chalazae  as  high  as  tubercles  on  which  ocelli  are 
placed,  about  as  conspicuous  as  those  of  thorax. 
c.  Prothoracic  legs  at  least  half  as  long  as  mesothoracie.  Pontia 

cc.  Prothoracic  legs  much  less  than  half  as  long  as  mesothoracie. 

Callidryas 

bb.  Head  with  chalazae  usually  lower  than  ocellar  tubercles;  when  a 

few  are  well  developed  they  are  not  one-fourth  as  large  as  those 

of  prothorax.  Synchloe 

aa.  Setae  of  head  usually  not  borne  on  chalazae,  those  of  front  always 

similar  to  those  laterad  of  the  epicranial  suture;  setae  of  body  all 

minute  and  similar. 

b.  Head  about  one-third  as  wide  as  abdomen,  deeply  retractile. 

Phoehis 
bb.  Head  at  least  half  as  wide  as  abdomen,  scarcely  retractile. 

c.  Body  setae  not  on  chalazae  or  on  very  small  ones.  Eurymus 

cc.  Body  setae  borne  on  distinct  chalazae,  higher  than  wide. 

Eurema 
Pontia  monuste  and  Pontia  protodice  have  many  of  the  chalazae 
much  larger  than  others,  while  P.  rapae  and  P.  napi  (including  var. 
oleracea)  usually  have  all  the  chalazae  small  and  subequal  in  size. 

Neither  of  the  two  species  of  Callidryas  have  been  available  but  the 


138  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [138 

genus  was  placed  in  the  table  on  the  authority  of  Scudder's  detailed 
description  of  C.  eubule. 

Synchloe  (=Anthocharis)  has  several  and  various  forms  of  larvae. 
In  S.  genutia  some  of  the  prothoracie  chalazae  are  very  large  and  those 
of  the  head  are  well  developed,  while  in  S.  sara  and  S.  olympia  the  setae 
of  the  head  and  prothorax  are  all  smaU  and  borne  on  small  chalazae. 

The  larva  of  Phoebis  argante  var.  maxima  Neum.  is  large  with  a 
small  retractile  head. 

The  bright  green  larva  of  Eurymus  philodice  is  well  known  in  the 
eastern  half  of  the  United  States.  It  has  a  pair  of  distinct  lateral  lines 
and  a  black  spot  below  the  line  on  each  segment.  E.  eury theme  which 
ranges  eastward  to  some  extent  from  its  home  in  the  Rocky  Mountains 
has  a  similar  larval  stage  except  that  the  black  spots  are  either  indistinct 
or  connected  from  one  segment  to  another. 

Eurema  nicippe  has  the  setae  all  about  the  same  size.  The  larger 
chalazae  of  the  head  are  larger  than  the  ocelli.  The  larva  of  E.  euterpe 
(==li$a)  is  less  than  three-fourths  of  an  inch  long  and  the  chalazae  of  the 
head  are  aU  small. 

Family  Papilionidae 

Larvae  of  the  Swallow-tail  butterflies  are,  like  the  adults,  beauti- 
fully decorated  and  outlined.  No  unpleasant  spines  or  horns  are  present 
to  discourage  the*  observer  and  no  discordant  colors  to  offend  him.  The 
structure  of  all  the  species  is  so  constant  that  it  is  necessary  to  have 
recourse  to  color  in  their  separation,  but  all  of  the  characters  used  are 
fixed  and  are  seldom  affected  by  alcoholic  or  other  means  of  preservation. 

Head  smaller  than  prothorax,  somewhat  retractile,  shorter  in  dor- 
sal than  in  ventral  portion ;  front  not  extending  half  way  to  top  of  head 
labrum  notched  to  about  half  its  depth  and  bearing  about  thirty  setae 
ocelli  six,  subequal  in  size,  fifth  much  closer  to  fourth  than  to  sixth 
secondary  setae  short.     Body  cylindrical,  usually  tapering  rather  ab- 
ruptly toward  the  head  and  gradually  toward  the  caudal  end,  usually 
widest  in  the  region  of  the  first  abdominal  segment;  setae  reduced  or 
absent  on  body  but  numerous  on  prolegs;  intersegmental  incisions  in- 
conspicuous; prolegs  short,  bearing  a  mesoseries  of  triordinal  crochets, 
sometimes  with  a  lateral  row,  forming  a  pseudocircle ;  lateral  crochets, 
when  present,  smaller  than  mesal,  and  biordinal.     Osmaterium  always 
present;  when  retracted  its  location  is  shown    by    a    long    transverse 
groove  on  the  dorsum  of  the  prothorax.    In  alcoholic  specimens  inserting 
the  points  of  a  small  pair  of  forceps  assures  the  observer  of  the  nature 
of  this  groove  and  does  no  damage. 

Scudder  divides  the  family  into  six  genera,  each  including  but  one 
or  two  species  found  in  New  England.    Dyar's  List  discards  three  of 


139]  LEPIDOPTEROUS  LARVAE  — FR ACKER  139 

them,  uniting  them  under  the  name  Papilio,  but  retains  Laertias  and 
Iphielides.  A  study  of  the  larvae  of  ten  species  of  Dyar's  Papilio, 
twice  as  many  as  Scudder  had,  shows  the  justification  of  Scudder's 
view,  four  distinct  forms  of  larvae  being  found.  As  it  would  be  very 
inconvenient  to  tabulate  species  of  the  family  when  using  Papilio  in  the 
broader  sense,  the  writer  has  returned  to  Scudder's  arrangement.  It 
might  also  be  mentioned  that  the  structure  of  the  pupae  upholds  his 
position. 

Genera  of  Papilionidae : 

a.  Body  bearing  several  rows  of  fleshy  filaments  or  filamentous  processes. 

Laertias 
aa.  Body  without  processes  of  any  kind,  except  osmateria. 

b.  Crochets  arranged  in  a  pseudocircle ;  metathorax  bearing  an  eye- 
spot, 
c.  Prothorax  bearing  a  small  transverse  black  shield;  lateral  line 
conspicuous;  first  abdominal  segment  bearing  two  black  spots 
near  its  caudal   margin  but  no  continuous  transverse  black 
band.  Euphoeades 

cc.  Prothoracic  shield  indistinct,  not  black;  lateral  line  inconspicu- 
ous; first  abdominal  segment  bearing  a  continuous  transverse 
black  or  yellow  band  near  its  caudal  margin.  Jasoniades 

bb.  Crochets  not  arranged  in  a  pseudocircle,  no  lateral  crochets  being 
present;  metathorax  not  bearing  an  eyespot. 
c.  Coloration  not  segmentally  arranged;  metathorax  with  a  slight 
transverse  dorsal  swelling.  Heraclides 

cc.  Coloration  segmentally  arranged;  metathorax  without  a  dorsal 
swelling, 
d.  Each  abdominal  segment  bearing  a  transverse  black  band 
marked  with  or  interrupted  by  circular  yellow  spots  and 
usually  bordered  by  two  transverse  green  stripes;  narrower 
black  transverse  intersegmental  stripe  also  present  in  each 
incision.  Papilio 

dd.  Each  abdominal  segment  bearing  a  series  of  five  transverse 
black  stripes.  Iphielides 

Laertias  philenor  is  distinguished  from  all  other  insect  larvae  by 
the  possession  of  several  pairs  of  fleshy  filaments  on  each  abdominal 
segment. 

Euphoeades  troilus,  in  addition  to  the  usual  metathoracic  eyespots, 
has  a  distinct  pair  on  the  first  abdominal  segment;  those  of  the  meta- 
thorax are  separated  by  a  distance  on  the  dorsum  subequal  to  the  width 
of  the  outer  circle  of  each  eyespot.  E.  palamedes  has  an  indistinct  pair 
on  the  first  abdominal  segment  and  the  metathoracic  pair  are  separated 


140  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [140 

by  a  distance  three  times  as  great  as  the  width  of  the  outer  circle  of 
each  spot. 

Jasoniades  glaucus  differs  from  other  species  of  the  genus  Jasoni- 
ades  in  that  the  eyespot  is  single;  that  is,  it  is  composed  of  a  circle 
enclosing  a  smaller  circle  and  a  short  rod,  but  is  not  associated  with  a 
smaller  circle  dorsad  of  the  large  one.  The  suture  bounding  the  front 
is  bluntly  angulated  at  about  the  middle.  In  J.  daunus  the  upper 
smaller  figure  of  the  double  eyespot  is  rounded  and  the  incisions  be- 
tween segments  5,  6,  and  7  are  marked  with  more  or  less  distinct  black 
lines.  J.  eurymedon  and  J.  rntulus  have  the  upper  figure  of  the  eyespot 
triangular  and  there  are  no  black  lines  in  the  abdominal  incisions,  or 
else  very  faint  ones.  The  former  has  the  sides  of  the  front  arcuate  while 
those  of  the  latter  are  straight  except  for  a  very  slight  curve  just  where 
they  unite. 

Heraclides  thoas  (^cresphontes)  is  notable  in  having  a  conspicu- 
ous white  mark  covering  segments  2,  3,  and  4  and  another  on  segments 
7  and  8,  while  the  rest  of  the  body  is  a  variegated  reddish  brown. 

There  remain  for  the  genus  Papilio  the  following  species :  machaon, 
hairdii,  zolicaon,  and  polyxenes,  all  of  which  are  very  similar  in  colora- 
tion. At  the  same  time  there  is  such  variation  within  species,  especially 
as  to  the  limits  of  these  markings,  that  any  suggestions  as  to  their  sepa- 
ration would  be  premature.  Papilio  cresphontinus,  americus,  and  indra 
from  the  southern,  states  and  P.  hrevicauda  from  New  England  probably 
also  belong  here  but  they  are  so  little  known  that  their  true  position  is 
somewhat  uncertain. 

Iphiclides  ajax  with  its  numerous  transverse  bands  is  quite  distinct 
from  all  other  members  of  the  family. 

Ithohalus.  No  specimens  of  the  two  species  of  this  southern  genus 
have  been  seen. 

Family  Parnassiidae 

The  Parnassians  seem  to  be  an  alpine  or  arctic  group,  for  their 
American  species  are  confined  to  the  Rocky  Mountains  and  Alaska. 
Their  scarcity  is  to  be  regretted,  for  they  retain  many  of  the  primitive 
characters  of  the  Papilios.  While  the  larvae  have  acquired  osmateria, 
they  still  retain  verrucae  and  conspicuous  setae  which  are  present  only 
in  the  earlier  larval  stages  of  Papilionidae.  As  adults  also,  the  venation 
is  of  the  type  found  in  Swallow-tails  but  the  prolongations  of  the  wings 
have  not  yet  been  developed.  The  following  description  is  based  on 
Parnassius  smintheus  of  the  Pacific  States  and  it  agrees  in  all  important 
particulars  with  P.  apollo  of  Europe.  The  only  other  species  recorded 
south  of  Alaska  is  P.  clodius. 

Head  rugose,  black,  about  one-third  the  diameter  of  the  abdomen, 


141]  LEPIDOPTEROUS  LARVAE  — FR ACKER  141 

somewhat  smaller  than  the  prothorax;  front  small,  wider  than  high^ 
reaching  about  half  way  to  top  of  head ;  labrum  moderately  emarginate, 
bearing  only  the  six  primary  setae  on  each  side ;  ocelli  six,  subequal  in 
size,  fifth  much  closer  to  fourth  than  to  sixth;  secondary  setae  of  epi- 
cranium  numerous  but  not  long.  Body  cylindrical,  scarcely  tapering, 
covered  with  short,  stout,  secondary  setae;  thoracic  segments  with  the 
verrucae  of  the  Kappa  and  Pi  groups,  and  sometimes  those  of  Beta  and 
Rho,  distinct.  Abdomen  with  Rho,  kappa,  eta,  mu,  and  Pi  forming 
distinct  and  separate  verrucae;  color  black,  except  for  several  yellow 
subdorsal  maculae  on  each  segment;  all  setae  black.  Thoracic  legs  well 
developed,  prolegs  with  a  mesoseries  of  biordinal  crochets  extending 
more  than  half  way  round  the  planta;  anal  prolegs  similar  to  ventral. 
Osmaterium  present. 

GLOSSARY 

In  the  list  of  words  on  the  following  pages  several  new  ones  are 
included  but  most  are  words  used  here  in  a  special  sense.  Smith's 
"Glossary  of  Entomology"  and  ''The  Standard  dictionary"  have  proved 
most  useful  in  its  preparation  altho  no  definitions  from  either  are  re- 
produced entire. 

Adfrontal  pieces,  n.  The  narrow  areas  on  the  cephalic  aspect  of 
the  head  just  laterad  of  the  front.     (Fig.  78.) 

Anal  prolegs,  n.    The  prolegs  of  the  last  abdominal  segment. 

Anal  segment,  n.    The  tenth  abdominal  segment. 

Annulet,  n.  One  of  the  small  rings  into  which  a  segment  is  divided 
by  transverse  constrictions. 

Armature,  n.  The  arrangement  and  form  of  all  the  setae  and 
processes  of  the  body  wall. 

Bigihious,  a.    With  a  pair  of  large  rounded  dorsal  swellings. 

Biordinal,  a.  Said  of  crochets  when  they  are  arranged  in  a  single 
series  but  are  of  at  least  two  alternating  lengths.    (Fig.  106.) 

Biserial,  a.  Said  of  crochets  when  they  are  arranged  in  two  con- 
centric rows.    See  multiserial. 

Bisetose,  a.  Consisting  of  or  bearing  two  setae;  said  of  a  group, 
such  as  Pi,  or  of  a  chalaza,  pinaculum,  etc. 

Chaetotaxy,  n.  The  arrangement  of  the  setae  of  a  particular  insect 
or  segment. 

Chalaza,  n.  A  small  chitinized  projection  of  cuticula  bearing  one 
seta  or  two  to  four  setae  on  separate  elevated  prominences,  between 
papillae  and  cornicula  in  size.     (Fig.  90.) 

Corniculum,  n.  A  small  horn-like  process  of  cuticula,  not  associ- 
ated with  primary  setae. 


142  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [142 

Coxa,  n.    The  first  segment  of  a  thoracic  leg. 

Crochet,  n.  One  of  the  series  of  chitinized,  hook-like,  cuticular 
structures  usually  arranged  in  rows  or  in  a  circle  on  the  prolegs  of 
lepidopterous  larvae;  also  known  as  "hooks". 

Epicranial  suture,  n.  The  suture  separating  the  front  from  the 
rest  of  the  epicranium,  shaped  like  an  inverted  Y,  with  the  front  be- 
tween the  arms  and  the  vertex  on  both  sides  of  the  stem.     (Fig.  72.) 

Epicranium,  n.  The  sclerite  which  constitutes  the  greater  part  of 
the  head  capsule. 

Fleshy  filament,  n.  A  flexible,  attenuate  process  of  the  body  wall, 
borne  by  some  butterfly  larvae.     (Fig.  92.) 

Front,  n.  The  sclerite  between  the  arms  of  the  epicranial  suture, 
usually  triangular  in  shape. 

Gibbous,  a.    With  a  large,  rounded,  dorsal  hump. 

Heteroideous,  a.  Said  of  crochets  when  a  well  developed  series  is 
flanked  by  a  row  of  smaller  crochets  on  each  side,  as  in  Arctiidae. 
(Fig.  100.) 

Homoideous,  a.    Not  heteroideous.    - 

Homology,  n.    See  Part  One,  p.  15. 

Homotypy,  n.    See  Part  One,  p.  15. 

Horn,  n.    A  stiff,  pointed,  unbranched,  cuticular  process. 

Mesoseries,  n.  A  band  of  crochets  extending  longitudinally  on  the 
mesal  side  of  a  proleg ;  when  curved,  varying  from  a  quadrant  to  slightly 
more  than  a  semicircle  in  extent.     (Fig.  105.) 

Moniliform,  a.  Possessing  distinct,  neck-like  constrictions  between 
successive  segments,  producing  a  resemblance  to  a  string  of  beads,  as  in 
many  leaf-miners. 

Multiserial,  a.  Arranged  in  several  concentric  rows,  as  the  crochets 
of  Hepialus,  Pseudanaphora,  etc.    (Figs.  94,  96.) 

Multisetiferous,  a.    Bearing  many  setae. 

Onisciform,  a.  Depressed  and  spindle-shaped,  like  an  oniseid,  as 
in  some  lycaenid  larvae. 

Osmaterium,  n.  An  eversible  gland  producing  an  odor,  as  in 
Papilionidae  and  Liparidae. 

PenelUpse,  n.  A  series  of  crochets  more  than  a  semicircle  in  extent 
and  less  than  a  complete  circle.  It  may  be  either  (a)  lateral,  covering 
at  least  the  lateral  half  of  the  planta,  as  in  Psychidae  (Fig.  85)  ;  or  (b) 
mesal,  covering  at  least  the  mesal  half  of  the  proleg  and  interrupted 
laterally,  as  in  Pyraustinae  (Fig.  98). 

Pinaculum,  n.  A  small,  flat,  chitinized  area  bearing  from  one  to 
four  setae. 

Plate,  n.  An  extended  chitinized  area  of  the  body  wall,  such  as  a 
shield ;  often  multisetiferous. 


143]  LEPIDOPTEROUS  LARVAE— FRACKER  143 

Primary  seta,  n.  A  seta  found  on  generalized  larvae  in  all  instars. 
When  contrasted  with  "secondary  setae"  this  term  also  applies  to  the 
few  subprimary  setae. 

Proleg,  n.  A  fleshy  abdominal  leg,  said  to  be  present  when  crochets 
are  present  even  when  there  is  no  fleshy  swelling, 

Pseudocircle,  n.  An  arrangement  of  crochets  consisting  of  a  well 
developed  mesoseries  and  a  row  of  small  hooks  on  the  lateral  aspect  of 
the  proleg.     (Fig.  97.) 

Scolus,  n.  A  spinose  projection  of  the  body  wall,  as  in  saturnian 
larvae.     (Figs.  73,  74.) 

Secondary  setae,  pi.  n.    Numerous  setae  having  a  general  distribu- 

tion^and  not  limited  to  verrucae  or  other  forms  of  tubercle.    See  page  23. 

Seta,  n.    A  ehitinized,  hair-like  projection  of  cuticula  arising  from 

a  single  trichogen  cell  and  surrounded  at  the  base  by  a  small  cuticular 

ring. 

Setiferous,  a.    Bearing  one  to  many  setae. 

Shield,  n.  A  ehitinized  plate  covering  the  greater  part  of  the  dor- 
sal half  of  a  segment. 

Sphingiform,  a.     Of  the  form  of  a  sphingid  caterpillar,  having  a 
cylindrical  body,  with  setae  very  short  or  wanting  and  no  other  arma- 
ture except  a  mediodorsal  horn  on  the  eighth  abdominal  segment. 
Spinule,  n.    One  of  the  short  lateral  branches  of  a  scolus. 
Stemapoda,  pi.  n.     Elongated  modifications  of  the  anal  prolegs  in 
certain  notodontid  larvae. 

Subprimary  seta,  n.  A  seta  having  a  definite  position  in  certain 
larvae  but  not  present  in  the  first  instar  of  generalized  groups.  See 
Part  One.    For  list  of  such  setae,  see  pages  39,  40. 

Suranal  plate,  n.  A  rather  heavily  ehitinized  area  on  the  dorsum 
of  the  last  abdominal  segment.     (Fig.  84.) 

Triordinal,  a.  Said  of  crochets  when  they  are  of  a  single  row  but 
of  three  alternating  lengths.     (Fig.  98.) 

Trisctose,  a.    Consisting  of  or  bearing  three  setae ;  compare  bisetose. 
Tuft,  n.    A  group  of  setae  arising  from  a  verruca. 
Uniordinal,  a.    Said  of  crochets  when  they  are  arranged  in  a  single 
row  and  are  of  a  single  length  throughout  or  shorter  toward  the  ends  of 
the  row;  opposed  to  biordinal.     (Figs.  101,  105.) 

Uniserial,  a.  Said  of  crochets  when  they  are  arranged  in  a  single 
row  or  series  with  their  bases  in  line.     (Figs.  101,  105,  etc.) 

Unisetose,  a.  Consisting  of  or  bearing  a  single  seta;  compare  bise- 
tose. 

Ventral  prolegs,  pi.  n.  Those  prolegs  ordinarily  borne  on  segments 
3,  4,  5,  and  6;  opposed  to  anal  prolegs;  bookless  prologs  are  sometimes 
also  borne  on  segments  2  and  7  and  these  are  also  known  as  ventral. 


144  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [144 

Yerricule,  n.  A  dense  tuft  of  upright  setae,  modified  from  a  ver- 
ruca or  seolus.     (Fig.  91.) 

Verruca,  n.  A  definitely  bounded,  somewhat  elevated  portion  of  the 
cuticle,  bearing  several  to  many  setae.     (Fig.  88.) 

Vertical  triangle,  n.  The  thinly  chitinized  dorsal  area  bounded 
laterad  by  the  caudal  projections  of  the  head  capsule  and  caudad^by  the 
prothorax.     (Fig.  72.) 


145]  LEPIDOPTEROUS  LARVAE  — FR ACKER  145 

BIBLIOGRAPHY 

The  following  list  includes  only  those  papers  to  which  reference  has 
been  made  on  preceding  pages : 

Beutenmuller,  Wm. 

Monograph   of  the   Sesiidae  of   North  America  North  of   Mexico.     Mem. 
Am.  Mus.  N.  H.,  i,  pt.  vi,  1900,  217. 
BuscK,  August. 

Notes  on  Microlepidoptera,  with  descriptions  of  New  North  American  Spe- 
cies.    Proc.  Ent.  Soc.  Wash.,  11,  1909,  87. 
On  the  Classification  of  the  Microlepidoptera.    do.  16,  1914,  46-54. 
Chapman,  T,  A. 

The  Classification  of  Gracilaria  and  Allied  Genera.     Entomologist,  35,  1902, 
pp.  81,  138,  159. 
Dyak,  Harrison  G. 

A  Classification  of  Lepidopterous  Larvae.    Ann.  N.  Y.  Acad.  Sci.,  8,  1894  194. 
Additional  Notes  on  the  Classification  of  Lepidopterous  Larvae.     Trans.  N. 

Y.  Acad.  Sci.,  14,  1895,  49. 
A  Classification  of  Lepidoptera  on  Larval  Characters.     Am.  Nat.,  29,  1895, 

1066. 
Life  Histories  of  New  York  Slug  Caterpillars. — Conclusion.     Jour.   N.   Y. 

Ent.  Soc,  8,  1899,  235. 
A  Century  of  Larval  Descriptions.     Entomologists'  Record,  13,  1901,  40. 
A  List  of  North  American  Lepidoptera.    Bui.  52,  U.  S.  Nat.  Mus.,  1902. 
The  Pericopid  Larvae  in  the  National  Museum.     Insecutor  Inscitiae  Men- 
struus,  2,  1914,  62. 
Felt,  E.  P. 

The  Scorpion-Flies.    Rept.  State  Ent.  N.  Y.,  10,  1895,  463. 
Forbes,  W.  T.  M. 

Field  Tables  of  Lepidoptera.     1906. 

A  Structural  Study  of  Some  Caterpillars.    Ann.  Ent.  Soc.  Am.,  3,  1910,  94. 
A   Structural  Study  of  the  Caterpillars. — H.     The   Sphingidae.     Ann.   Ent. 
Soc.  Am.,  4,  191 1,  261. 

HOFMANN,   O. 

t)ber   die   Anordnung   der   borstentragenden   Warzen   bei    den    Raupen   der 
Pterophoriden.     Illus.  Zeitschr.  Ent.,  3,  1898,  129. 

MiJLLER,  WiLHELM. 

Sudamerikanischer  Nymphalidenraupen.     Zool.  Jahrb.,   Zeitschr.   f.   Syst.,   i, 
1886,  417. 
Packard,  A.  S. 

Monograph  of  the  Bombycine  Moths.     Part  I.     Notodontidae.     Mem.  Nat. 
Acad.  Sci.,  Vol.  7,  1895. 
Quail,  Ambrose. 

Notes  on  Cossidae.    Entomologist,  y;,  1904.  93- 

On  the  Tubercles  of  Thorax  and  Abdomen  in  First  Larval  Stage  of  Lepi- 
doptera.   Ibid.,  p.  269. 


146  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [146 


^.^ 


Reaumur. 

Memoires  pour  servir  a  I'histoire  des  Insectes.     1736-42. 
SCUDDER,  S.  H. 

The  Butterflies  of  the  Eastern  United  States  and  Canada.     1889. 
SiLTALA,  A.  J. 

Trichopterologische  Untersuchungen.     No.  2.     Zool.  Jahrb.,  Suppl.^g,   1907, 
pp.  309-626,  esp.,  pp.  356-375. 
Spuler,  Arnold. 

Die  Schmetterlinge  Europas.     Bd.  i,  1908,  p.  ix. 
Tsou,  Y.  H. 

The  Body  Setae  of  Lepidopterous  Larvae.     Trans.  Am.  Micr.  Soc,  22,  1914. 
223-260.  This  paper  was  written  simultaneously  with  the  one  presented  here- 
with.   The  results  agree  in  the  main  as  each  was  cognizant  of  the  other's 
work. 
Walsingham,  Lord. 

Biologia  Centrali-Americana.     Lepidoptera  Heterocera.     Vol.  4,   incomplete, 
191 1 — . 
Wood,  J.  H. 

Notes  on  Earlier  Stages  of  the  Nepticulae.     Ent.  Monthly  Mag.  (2),  5,  1894, 
PP-  I,  43,  93.  ISO,  272. 


147]  LEPIDOPTEROUS  LARVAE— FR ACKER  147 


•  EXPLANATION    OF   PLATES 

Plates  I  to  VII  and  X  consist  entirely  of  setal  maps.  In  these  the 
top  line  of  the  diagram  represents  the  dorsomeson  and  the  bottom  line 
the  ventromeson.  Thus  the  map  shows  the  entire  left  half  of  the  seg- 
ment, the  thoracic  leg  or  the  proleg,  as  the  case  may  be,  being  indicated 
by  an  ellipse. 

The  body  segments  are  numbered  I,  II,  III,  1,  2,  3,  4,  5,  6,  7,  8,  9, 
and  10,  the  Roman  numerals  ^referring  to  the  thorax  and  the  Arabic  to 
the  abdomen.  Care  should  be  taken  in  using  this  in  connection  with  the 
statements  of  other  authors.  For  example,  the  head  is  counted  as  "joint 
1",  the  prothorax  as  "joint  2",  etc.,  in  Dyar's  descriptions.  Dyar  has 
also  entirely  failed  to  note  segment  9  and  thus,  while  segment  8  is  his 

*  *  joint  12 ' ',  the  anal  segments  is  called  ' '  joint  13  ".    In  the  setal  maps  the 
number  of  each  segment  is  given  in  the  lower  left  hand  corner. 

In  all  the  figures,  both  of  setal  maps  and  other  structures,  the  head 
is  at  the  left. 

The  following  is  a  list  of  all  the  setae.  Each  is  indicated  by  a 
lower  case  Greek  letter: 


a  alpha 

e  theta 

p  rho 

P  beta 

K  kappa 

o-  sigma 

y  gamma 

A  lambda  (rare) 

T  tau 

8  delta 

IX.  mu 

<l>  phi 

e  epsilon 

V  nu 

CO  omega 

t]  eta 

TT  pi 

Certain  definite  groups  of  setae  are  indicated  by  capital  Greek 
letters.  They  are:  Beta,  B  (a-f-^)  ;  Kappa,  K  (^/c+17)  Rho,  P 
(c-|-p)  ;  Pi,  n  (v+TT  on  thorax,  v+7r-|-T  on  abdomen)  ;  Tau,  T,  some  or 
all  of  the  three  setae,  tau,  phi,  and  omega,  the  first  of  which  is,  how- 
ever, more  closely  associated  with  the  Pi  group  on  abdominal  segments. 
Of  the  Kappa  group,  theta  is  usually  absent. 

The  ocelli  are  numbered  as  in  Fig.  70. 

The  numerals  applied  to  the  head  setae  are  taken  direct  from 
Forbes  (1910),  who  uses  Dj^ar's  system  for  them.  In  his  paper  will  be 
found  large  numbers  of  drawings  of  head  parts,  and  for  that  reason 
only  a  few  have  been  figured  here. 


1491  LEPIDOPTEROUS  LARVAE— FRACKER  149 


PLATE  I— II 


ISO  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [150 


EXPLANATION  OF  PLATE  I 
Setal  Maps.    See  page  147 

Fig.  I.  Hypothetical  type  showing  the  twelve  primary-  setae.  In  addition  three  of 
the  more  usual  subprimaries  are  dotted  in.  The  spiracle  is  shown  in 
both  the  prothoradc  (a)  and  abdominal  (b)  positions. 

Figfs.  2,  3,  4.  Hepialus  mustelinus,  Hepialidae,  Jugatae.  Prothorax,  mesothorax, 
and  third  abdominal  segment,  first  instar.  Adapted  from  figures  by 
Dyar   (1895b). 

Fig.  5-    Hepialus  humuli.    Prothorax  and  mesothorax  of  mature  larva. 

Fig.  6.    Hepialus  humuli.    Abdominal  segments  i  to  3  of  mature  larva. 

Fig.  7.  Pseudanaphora  arcanella,  Acrolophidae,  Tineoida.  Prothorax  and  meso- 
thorax of  mature  larva. 

Fig.  8.    Pseudanaphora  arcanella.    Abdominal  segments  i  to  3  of  mature  larva. 

'    EXPLANATION  OF  PLATE  II 

Setal  Maps. 

Fig.    9.    Typical  mesothorax  of  Frenatae,  labeled  with  Greek  letters. 

Fig.  ID.     Typical    proleg-bearing    abdominal    segment    of    Frenatae,    labeled    with 

Greek  letters. 
Fib.  II.    Typical  mesothorax  of  Frenatae,  labeled  according  to  Ehar's   system. 
Fig.  12.    Typical  proleg-bearing  abdominal  segment  of  Frenatae,  labeled  according 

to  D3-ar*s  system. 
Figs.  13,  14.    Hepialus  humuli,  Hepialidae.    Abdominal  segments  6  to  10  of  mature 

larva.     (Tau  and  omega  are  transposed  in  Fig.  14.) 
Figs.  15,  16.    Pseudanaphora  arcanella,  Acrolophidae.    Abdominal  segments  6  to  10 

of  mature  larva. 


a 

^   ;    ^- 

/? 

->/ 

—     :      -^ 

a 

'S    E 

-    i   — 

/o 

H 

n 

b                      a 

V 

^^^ 

TT 

T 

^n 

CO 

*u 

(T 

PLATE    I 


PLATE   II 


151]  LEPIDOPTEROUS  LARVAE— PR  ACKER  151 


PLATES  III— IV 


152  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [152 


EXPLANATION  OF  PLATE  III 
Setal  Maps. 

Figs.  17,  18,  19,  20.  Feltia  gladiaria,  Noctuidae.  Pro  thorax,  mesothorax,  and  first 
and  second  abdominal  segments  respectively;  first  instar. 

Figs.  21,  22,  23,  24.  Feltia  gladiaria,  Noctuidae.  Same  segments  of  the  mature 
larva. 

Figs.  25,  26,  27,  28.  Hyphantria  cunea,  Arctiidae.  Same  segments  of  the  mature 
larva. 


EXPLANATION  OF  PLATE  IV 
Setal  Maps. 

Figs.  29,  30.  Feltia  gladiaria,  Noctuidae.  Abdominal  segments  6  to  10  respect- 
ively; first  instar. 

Figs.  31,  32.  Feltia  gladiaria,  Noctuidae.  Abdominal  segments  6  to  10  respect- 
ively; mature  larva. 

Figs.  22>  34.  Hyphantria  cunea,  Arctiidae.  Abdominal  segments  6  to  10  respect- 
ively; mature  larva. 


\' 


0 

V        ' 


71 


17 


18 


?     " 


V 


TT 


(T 


/ 


n 


19 


20 


/?    «- 


n 


(T 


0 


23 


B 

^ 

P  P 

^£^ 

d 

^^- 

;< 

n 

^ 

/I 

■  ^ 

(T 

27 


PLA'lE  111 


PLATE    IV 


153]  LEPIDOPTEROUS  LARVAE— FR ACKER  153 


PLATE  V 


154  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [154 


EXPLANATION  OF  PLATE 
Setal  Maps. 

Figs.  35,  36,  27,  38.    Atteva  aurea,  Yponomeutidae.    Prothorax,  mesothorax,  fourth 

and  ninth  abdominal  segments  respectively. 
Figs.  39,  40,  41,  42.     Cydia  pomonella,  Tortricidae.     Same  segments. 
Figs.  43,  44,  45,  46. '   Psorosina     (Canarsia)     hammondi,     Phycitinae,     Pyralididae. 

Same  segments. 


a 

7 


y--— 


/ 


— ^-    a 

P       £ 

e    V 


n 


"^     |(r       [n 


/ 


p 
e 

n 


a 


n 


i_:^ 


ft 


— / 


n 


35 


36 


37 


7 


K 


P    P 


N 


/7 


cr 


^ 
^ 


P 


39 


er 


o— 


-!x- 


/? 

^       ^ 


TT 


n 


(^? 


0 

/ 


y 


^,5 

4  X 


/^ 


38 


K 

TT 


40 


41 


42 


(^-. 


46 


PLATE  V 


155]  LEPIDOPTEROUS  LARVAE  — FRACKER  155 


PLATE  VI 


156  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [156 


EXPLANATION  OF  PLATE 

Setal  Maps. 

Fig.  47.  Phycitinae,  Pyralididae.  Prothorax  of  an  unidentified  species  showing 
arrangement  of  setae  similar  to  that  of  Melitara. 

Figs.  48,  49.  Loxostege  similalis,  Pyraustinae,  Pyralididae.  Third  and  ninth  ab- 
dominal segments  respectively. 

Fig.  so.    Galleria  mellonella,  Galleriinae,  Pyralididae.    Mesothorax. 

Figs.  51,  52,  53,  54.  Scardia  fiskeella,  Tineidae.  Prothorax,  mesothorax,  third  and 
ninth  abdominal  segments  respectively. 

Fig.  55.     Thyris  fer.estrella,  Thyrididae.     Ninth  abdominal  segment  ^ 

Fig.  56.    Gelechia  sp.,  Gelechiidae.    Ninth  abdominal  segment. 

Fig.  57.    Sanninoidea  exitiosa,  Aegeriidae.    Ninth  abdominal  segment. 

Fig.  58.    Thyridopteryx  ephemeraeformis,  Psychidae.     Third   abdominal   segment. 


PLATE  VI 


157]  LEPIDOPTEROUS  LARVAE  — FRACKER  157 


PLATE  VII 


158  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [158 


EXPLANATION  OF  PLATE 

Setal  Maps  of  Abdominal  Segments. 

Fig.  59.    Acoloithus  falsarius,  Pyromorphidae.     Segment  5. 

Fig.  60.    Nola  cristatula,  Nolidae.     Segment  5. 

Fig.  61.     Oxyptilus  delavaricus,   Pterophoridae.     Segment  5. 

Fig.  62.     Calliszia  inornata,  Epiplemidae.     Segment  5. 

Fig.  63.     Cleora  pampinaria,  Geometridae.     Segments  5,  6,  7. 

Fig.  64.     Thyatira  batis,  of  Europe,  Thyatiridae.     Segment  4. 

Figs.  65,  66.    Acronycta  sp.,  Noctuidae.     Segments  6  and  7.     Note  fusion  of  ver- 

rucae  kappa  and  eta  on  segment  7. 
Figs.  67,  68.     Syntomis  phegea,  of  Europe,  Syntomidae.     Segments  6  and  7.     Note 

that  kappa  is  in  same  position  on  segment  7  as  on  segment  6. 


yy 


n 


62 


-  - 

/? 

^  ' — 

0 

/> 

\ 
/ 

/ 

X 
/" 

_   \ 

A 

4        VSc 

0- 

64 


PLATE  VII 


159]  LEPIDOPTEROUS  LARVAE— FR ACKER  159 


PLATE  VIII 


160  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [160 


EXPLANATION  OF  PLATE 

Fig.  69.  Thyridopteryx  ephemeraeformis,  Psychidae.  Showing  portion  of  protho- 
rax  which  bears  peculiar  horizontal  spiracle. 

Fig.  70.    Acrohasis  betulella,  Pyralididae.     Ocellar  group. 

Fig.  71.    Plodia  interpunctella,  Pyralididae.     Ocellar  group. 

Fig.  72.  Zeuzera  pyrina,  Cossidae.  Head,  cephalodorsal  aspect,  showing  the  very 
large  mandibles. 

Fig.  73.  Euptoieta  claudia,  Nymphalidae.  Subdorsal  scolus  of  third  abdominal 
segment. 

Fig.  74.  Polygonia  interrogationis,  Nymphalidae.  Subdorsal  scolus  of  eighth  ab- 
dominal segment. 

Fig.  75.    Ocellar  arrangement  similar  to  that  of  Podosesia,  Aegeriidae. 

Fig.  76.    Eurycittarus  confederata,  Psychidae.     Front,  adfrontals,  and  their  setae. 

Fig.  yj.    Sanninoidea  exitiosa,  Aegeriidae.    Ocellar  group. 

Fig.  78.  Thyridopteryx  ephemeraeformis,  Psychidae.  Head.  In  all  the  head  fig- 
ures of  the  plate :  fp — frontal  puncture ;  f — frontal  seta ;  afi — first 
adfrontal  seta ;  afii — second  adf rontal  seta ;  afp — adfrontal  puncture, 
borne  on  adfrontals  between  adfrontal  setae. 

Fig.  79.    Estigmene  acraea,  Arctiidae.    Spiracle. 

Fig.  80.    Depressaria  sp.,  Oecophoridae.     Ocellar  group. 

Fig.  81.    Anacampsis  populella,  Gelechiidae.    Ocellar  group.  « 

Fig.  82.     Oiketicus  abbotii,  Psychidae.    Front  and  adfrontals. 

Fig.  83.    Solenobia  walshella,  Psychidae.    Front  and  adfrontals. 

Fig.  84.     Suranal  plate  of  a  European  species  of  Agapetidae. 

Fig.  85.     Thyridopteryx  ephemeraeformis,  Psychidae.    Proleg. 

Fig.  86.    Celama  triquetrana,  Nolidae.    Ocellar  group. 

Fig.  87.    Nola  apera,  Nolidae.    Ocellar  group. 


PLATE  VIII 


161]  LEPIDOPTEROUS  LARVAE— FR ACKER  161 


PLATE  IX 


162  ILLINOIS  BIOLOGICAL  MONOGRAPHS  [162 


EXPLANATION  OF  PLATE 

Fig.    88.    Tjrpical  verruca  of  Arctiidae;  Estigmene  acraea. 

Fig.  89.  Drepana  harpagula,  of  Europe,  Platypterygidae.  Lateral  aspect  showing 
anal  process. 

Fig.    90.    Typical  chalaza;  Utetheisa  bella,  Arctiidae. 

Fig.    91.     Typical  verricule ;  Acronycta  rubricoma. 

Fig.    92.    Typical  fleshy  filament;  lateral  aspect  of  Anosia  plexippus,  mesothorax. 

Fig.  93.  Nepticula  sp.,  Nepticulidae.  Lateral  aspect  of  the  three  thoracic  and 
first  two  abdominal  segments  showing  the  first  three  pairs  of  fleshy 
legs,  and  their  location. 

Fig.    94.    Adela  degeerella,  of  Europe,  Incurvariidae.    Crochets. 

Fig.    95.    Plutella  maculipennis,  Yponomeutidae.     Proleg,  mesal  aspect. 

Fig.  96.  Pseudanaphora  arcanella,  Acrolophidae.  Ventral  aspect  of  proleg,  show- 
ing crochets  arranged  in  a  multiserial  circle. 

Fig.  97.  Drepana  harpagula,  Platypterygidae.  Latero-ventral  aspect  of  proleg, 
showing  crochets  arranged  in  a  pseudocircle. 

Fig.  98.  Psorosina  hammondi,  Pyraustinae,  Pyralididae.  Ventral  aspect  of  pro- 
leg,  showing  crochets  arranged  in  a  mesal  penellipse. 

Fig.  99.  SanninoideA  exitiosa,  Aegeriidae.  Crochets  arranged  in  transverse 
bands. 

Fig.  100.  Estigmene  acraea,  Arctiidae.  Mesal  aspect  of  proleg;  crochets  heteroi- 
deous,  uniordinal,  arranged  in  a  mesoseries. 

Fig.  101.  Pyralis  farinalis,  Pyralidinae,  Pyralididae.  Crochets  biordinal,  arranged 
in  a  complete  circle. 

Fig.  102,  Lycaena  coridon,  Lycaenidae.  Proleg,  mesal  aspect,  showing  interrupted 
mesoseries  and  fleshy  lobe. 

Fig.  103.     Ornix  geminatella,  Gracilariidae.    Crochets  of  abdominal  segment  3. 

Fig.  104.    Zygaena  punctum,  Zygaenidae,  of  Europe.     Spiracle. 

Fig.  105.  Scolecocampa  Uburna,  Noctuidae.  Mesal  aspect  of  proleg;  crochets  uni- 
ordinal, arranged  in  a  mesoseries ;  also  homoideous. 

Fig.  106.  Satumiidae.  Mesal  aspect  of  proleg;  crochets  biordinal,  arranged  in  a 
mesoseries. 


103 


104 


105 


106 


r^ 


PLATE   IX 


163]  ILLINOIS    BIOLOGICAL   MONOGRAPHS  163 


PLATE  X 


164  LEPIDOPTEROUS   LARVAE— FRACKER  [164 


EXPLANATION  OF  PLATE 

Fig.  107.  Samia    cecropia,    Satumiidae.      Prothorax,    mesothorax,    and    first    and 

third  abdominal  segments. 

Fig.  108.  Samia  cecropia,  Satumiidae.    Abdominal  segments  8  and  9. 

Fig.  109.  Autotneris  io,  Hemileucidae.    Abdominal  segments  8  and  9. 

Fig.  no.  atheroma  regalis,  Ceratocampidae.    Abdominal  segments  8  and  9. 

Fig.  III.  Anisota  rubicunda,  Ceratocampidae.    Abdominal  segments  8  and  9. 

Fig    ri2.  Polygonia  interrogationis,  Nymphalidae.     Abdominal  segments  8  and  9. 


PLATE   X 


INDEX  TO  GENERA  AND  HIGHER  GROUPS 


Achroia,  88 

Acoloithus,  96 

Acrobasis,  90 

Acrolophidae,  51,  63,  66 

Acronycta,  104,  112,  113 

Aculeata,  62,  64-66 

Adela,  65 

Adelocephala,  123,  125 

Aegeria,  75,  76 

Aegeriidae,  51,  63,  75-77 

Agapema,  122,  123 

Agapetidae,  54,  59,  127,  131 

Agaristidae,  54,  114 

Aglais,  135 

Aglia,  121 

Agonopteryx,  85 

Agraulis,  131,  134 

Agriopodes,  112,  113 

Alcathoe,  77 

Alceris,  73 

AUonyma,  82 

Alypia,  114 

Ammalo,  115 

Anacampsis,  84 

Anaea,  131,  133,  135 

Anaphorinae,  66 

Anarsia,  84 

Ancylis,  73 

Androloma,  114 

Anisopteryx,  loi 

Anisota,  123,  125 

Anosia,  130 

Anthocharis,  138 

Antispila,  69 

Apantesis,  115 

Apatelodes,  48,  103,  104 

Apostraphia,  131 

Arachnis,   117 

Archips,  73 

Arctia,  115 

Arctiidae,  53,  55,  104,  112,  113,  114-118 

Argynnis,  134 

Arogalea,  83 

Asciodes,  93 


165 


Aspidiscus,  69 
Atteva,  70 

Automeris,  120,  122,  124 
Auzatidae,  loi 

B 
Basilarchia,  135 
Basilona,  122,  125 
Bedellia,  68 
Bembecia,  77 
Bombycidae,  57,  102 
Bombycoidea,  29-32,   100-119 
Bombyx,  102 
Blastobasidae,  53,  85 
Brachiloma,  81 
Brenthia,  82 
Brenthis,  134 
Brephos,  loi 

Bucculatrigidae,  50,  66,  67 
Bucculatrix,  67 

C 
Calledapteryx,  100 
Callidryas,  137 
Callizzia,    100 
Callosamia,  122,  123 
Calycopys,   129 
Cameraria,  71 
Canarsia,  90 
Carama,  97 
Cemiostoma,  68 
Cenopis,  73 

Ceratocampidae,  120-126 
Cercyonis,  132 
Cerostoma,  69 
Cerura,  107 
Chalcosidae,  95 
Chalia,  79 
Charadra,  113 
Charidryas,  135 
Chilo,  91 
Chimabache,  85 
Chlorippe,   135 
Chlosyne,  135 
Choreutis,  82 
Chrysophanus,  129 
Cicinnus,  98 


166 


LEPIDOPTEROUS   LARVAE— FR ACKER 


[166 


Cinclidia,  134 
Cissia,   132 
Citheronia,  122,  125 
Clydonopteron,  88 
Cochlidiidae,  49,  65,  96,  97 
Coenonympha,  132 
Coleophora,  80 
Coleophoridae,  49,  51,  65,  80 
Coloradia,  120,  122,  125 
Copidryas,  114 
Coptotriche,  66 
Cosmopterygidae,  52,  80,  86 
Cosmopteryx,  86 
Cosmosoma,  119 
Cossidae,  30,  50,  52,  71,  yy 
Cossula,  yy,  78 
Cossus,  34,  yy,  78 
Crambus,  91 
Cryptolechia,  85 
Ctenucha,  119 
Cyaniris,  129 
Cybalomia,  91 
Cycnidioidea,  80 
Cydia,  71,  72 
<  D 

Dalceridae,  95 
Dasylophia,  108 
Dasystoma,  85 
Datana,  107,  113 
Demas,  112,  113 
Depressaria,  85 
Desmia,  92 
Diacrisia,  117 
Diaphania,  93 
Dichogama,  92 
Dicymolomia,  91 
Didugua,  109,  no 
Dioptidae,  55,  no 
Doa,  55,  113,  114 
Drepana,  102 
Dysodia,  74,  75 
Dyspessa,  78 

E 
Ecdytolophia,  yz 
Ecpantheria,  115 
Ectoedemia,  64 
Ectypia,  115 
Elachista,  80 
Flachistidae,  80 
Elasmopalpus,  89 
Ellida,  108 
Elophila,  93 


Enarmonia,  y^ 
Enodia,  132 
Epagoge,  73 
Ephestia,  90 
Epicnaptera,  103 
Epicorsia,  93 
Epimartyria,  60 
Epipaschia,  88 
Epipaschiinae,  88,  90 
Epiplemidae,  56,  100,  106 
Epipyropidae,   54,  96 
Epipyrops,  96 
Episimus,  y^ 
Eriocephala,  60 
Estigmene,  117 
Ethmia,  81 

Ethmiidae,  53,  56,  68,  81 
Eubaphe,   116 
Eucereon,  119 
Euchaetias,  115 
Eucosma,  y2 
Eudeilinea,  loi 
Eugonia,  135 
Eulonche,  113 
Eumaeus,  128 
Euphoeades,  139 
Euphydryas,  134 
Euproctis,  105 
Eupseudosoma,  115 
Eupterotidae,  48,  57,  103 
Euptoieta,  133,  134 
Eurema,  137,  138 
Eurycittarus,  79 
Eurymus,  137,  138 
Euschausia,  116 
Eustixia,  91 
Euvanessa,  135 
Euzophera,  89 
Everes,  129 
Evergestis,  92 
Exartema,  72 

F 
Falcaria,  102 
Feniseca,  128 
Fentonia,  107,  109 
Frenatae,  29-32,  61-141 

G 
Galleria,  87,  88,  94 
Gelechia,  80,  84 
Gelechiidae,  49,  50,  52,  65,  83 
Gelechioidea,  69,  71,  80-86 
Geometridae,  57,  70,  100 


167] 


INDEX 


167 


Geschna,  93 

Gloveria,  103 

Gluphisia,  107,  109 

Gnorimoschema,  84 

Gonioterma,  82 

Gracilaria,  71 

Gracilariidae,  49,  50,  62,  66,  70-71 

Gynaephora,  105 

H 
Habrosyne,  106 
Halisidota,  115 
Haploa,  116 
Harpyia,  107 
Harrisimemna,  112 
Harrisina,  96 

Heliconiidae,  58,  120,  127,  131 
Heliodinidae,  49,  51,  68,  80 
Hellula,  91 
Hemerocampa,  105 
Hemerophila,  82 
Hemerophilidae,  53,  68,  82 
Hemihyalea,  115 
Hemileuca,  120,  122,  123,  124 
Hemileucidae,  120-125 
Heodes,   129 

Hepialidae,  24-29,  51,  60,  63 
Hepialus,  24-29,  60,  63 
Heraclides,  139,  140 
Hesperiidae,  58,  127 
Heterocampa,  107,  109 
Heterocera,  61 
Heteropacha,  103 
Heydenia,  86 
Holcocera,  86 
Homaledra,  86 
Hulstea,  89 
Hylesia,  126 
Hymenia,  92 
Hyparpax,  107,  108 
Hypatus,  130,  131 
Hyperaeschra,  108,  109,  IIO 
Hyphantria,  116 
Hyphoraia,  116 
Hypoprepia,  118 
Hypopta,  78 
Hypsopygia,  88 

I 
lanassa,  108,  iio 
Ichthyura,  107 
Ide,  81 
mice,  118 
Incurvaria,  65 
Incurvariidae,  50,  65 


Inguromorpha,  78 
Iphiclides,  139,  140 
Isia,  115 
Ithobalus,   140 
Ithomiidae,  127,  130 

J 
Jasoniades,  139,  140 
Jocara,  88 
Jugatae,  60 
Junonia,  135 

L 
Lacosoma,  86,  98 
Lacosomidae,  56,  98 
Laertias,  139 
Lagoa,  97 

Lasiocampidae,  57,   102 
Laverna,  86 
Lemonias,  134 
Leptarctia,   116 
Lerina,  116 
Leucoptera,  68 
Libythea,  130 
Libytheidae,  59,  127,  130 
Limenitis,  135 
Limnoecia,  86 
Liparidae,  55,  104,  105 
Lithariapteryx,  68 
Lithocolletis,  71 
Lithosiidae,  53,  113,  118 
Litodonta,  109 
Lophodonta,  109 
Loxostege,  91 

Lycaenidae,  58,  127-128,  129 
Lycomorpha,  119 
Lycorea,  130 
Lymire,  119 

Lymnadidae,  58,  127,  130 
Lyonetiidae,   51,  67 

M 
Machimia,  85 

Macroheterocera,  64,  100-126 
Macrolepidoptera,  63,  100-141 
Macrurocampa,  107 
Malacosoma,   103 
Marmara,  71 
Megalopyge,  97 
Megalopygidae,  54,  96,  97 
Megathymidae,  58,  127,  128 
Megathymus,  128 
Melalopha,  107,  113 
Melitara,  89 
Melittia,  76 
Memythrus,  76 


168 


LEPIDOPTEROUS   LARVAE— FR ACKER 


[168 


Meroptera,  89 

Mestra,  135 

Metzneria,  83 

Microlepidoptera,  z\,  48,  61-99 

Micropterygidae,  24,  49,  60,  63 

Micropterygoidea,  60 

Micropteryx,  60 

Mieza,  70 

Mineola,  90 

Misogada,  109 

Mitoura,  128 

N 
Nadata,  109 
Nathalis,  137 
Nealyda,  83 
Neonympha,  132 
Nepticula,  64 
Nepticulidae.  49,  64 
Nerice,  107,  108 

Noctuidae,  29-31,  54,  56,  63,  70,  111-114 
Nolidae,  54,  70,  98 
Nomiades,  129 
Non-aculeata,  62 
Notodontidae,  48,  55,  106-110 
Notolophus,  105 
Nycteolidae,   iii 

Nymphalidae,  12,  58,  59,  120,  127,  132-136 
Nymphula,  93 

O 
Odontosia,  108,  no 
Oecophora,  85 
Oecophoridae,  52,  83,  85 
Oeneis,  132 
Oiketicus,  70 
Olene,  105 
Olethreutes,  73 
Omphalocera,  88,  90 
Opostega,  64 
Oreta,  102 
Orneodes,  94 
Orneodidae,  50,  94 
Ornix,  71 
Oxyptilus,  95 

P 
Pachyzancla.  92 
Panthea,  112,  113 
Pantographa,  93 
Papilio,   139,   140 
Papilionidae,  59,  127,  138-140 
Paradosis,  93 
Parharmonia,  76 
Parnassiidae.  59,  127,  140-141 
Pamassius,  140 


Pericopidae,  56,  in 

Pheosia,  108 

Philosamia,  121,  123 

Philotes,  129 

Phlyctaenia,  92 

Phoebis,  137,  138 

Phragmatobia,  116 

Phragmatoecia,  77 

Phryganidia,  no 

Phthorimaea,  84 

Phyciodes,  134 

Pieridae,  59,  127,  136-138 

Platoeceticus,  79 

Platynota,  73 

Platyprepia,  115 

Platypterygidae,  55,  56,  loi 

Platyptilia,  95 

Plodia,  90 

Plutella,  69 

Podosesia,  76 

Polygonia,   135 

Polygrammate,  112,  113 

Pontia,  137 

Porthetria,  104,  105 

Prionoxystus,  30,  77,  78 

Prodoxidae,  49,  64 

Prodoxus,  65 

Proleucoptera,  68 

Prolimacodes,  95 

Pronuba,  65 

Pseudanaphora,  31,  63,  66 

Pseudogalleria,  72 

Pseudohazis,  120,  122,  123,  124 

Pseudomya,  119 

Pseudothyatira,  106 

Psilocorsis,  85 

Psorosina,  89 

Psychidae,  52,  78 

Pterophoridae,  13,  54,  56,  69,  86,  94 

Pterophorus,  95 

Rilodon,   108,  no 

Pyralididae,  35,  50,  87-94 

Pyralidoidea,  63,  64,  86-95 

Pyralis,  88,  90 

Pyrausta,  92 

Pyrisita,  137 

Pyrotnorpha,  96 

Pyromorphidae,  56,  95,  96 

R 
Recurvaria,  84 
Rhopalocera,   126-141 
Riodinidae,  58,  127,  129 
Rothschildia,  121,  123 


169] 


INDEX 


169 


Rusticus,  129 


S 


Salebria,  89 

Salobrana,  88 

Samia,  120,  122,  123 

Sanninoidea,  y6 

Saturnia,  120,  122,  123,  133 

Saturniidae,  27,  120-123 

Saturnioidea,  31,  48,  57,  120-126,  133 

Satyrodes,  132 

Scardia,  67 

Scepsis,  119 

Schizura,  107,  108,  no 

Schreckensteinia,  53,  68,  69 

Sciaphila,  72 

Scoparia,  94 

Scythridinae,  80 

Scythris,  56,  69,  70 

Seirarctia,  117 

Sesia,  75 

Simyra,  113 

Sitotroga,  83 

Solenobia,  79 

Speyeria,  133,  134 

Sphingidae,  57,  126 

Sphingoidea,  126 

Stenoma,  81,  82 

Stenomidae,  53,  81 

Sthenopis,  60 

Stilbosis,  86 

Swammerdamia,  70 

Sylepta,  92 

Symmerista,  108 

Synchloe,   137,  138 

Syntomeida,  119 

Syntomidae,  55,  in,  118,  119 

Syntomis,  119 

Syssphinx,  123,  125 

T 
Tacoma,  90 
Telea,  122,  123 
Telphusa,  84 
Terastia,  92 
Tetralopha,  88 


Thauma,  126 
Thecla,  129 
Thessalia,  135 
Thiodia,  72 
Tholeria,  91 
Thyatiridae,  53,  57,  106 
Thyrididae,   51,  74 
Thyridopteryx,  79 
Thyridopyralis,  75,  89 
Thyris,  74,  75 
Tineidae,  51,  63,  66,  67 
Tineoidea,  61,  66-68 
Tineola,  67 
Tischeria,  66 
Tischeriidae,  49,  66 
Tmetocera,  y2 
Tolype,  103 

Tortricidae,  52,  63,  71-74 
Tortrix,  73 
Trichostibas,  83 
Trichotaphe,  84 
Triprocris,  95 
Tropea,  121,  123 

U 
Uranotes,  129 
Utetheisa,  53,  113,  114 

V 
Valentinia,  86 
Vanessa,  135 
Vespamima,  y6 
Vitula,  90 

X 
Xylorictidae,  81 

Y 
Yponomeuta,  70 

Yponomeutidae,  51,  53,  56,  63,  69-70 
Yponomeutoidea,  68-70 
Ypsolophus,  84 

Z 
Zelleria,  70 
Zerene,  137 
Zeuzera,  77,  78 
Zygaenidae,  96 
Zygaenoidea,  63,  64,  95-98,  128 


i 


UNIVERSITY  OF  ILLINOIS-URBANA 

570.SILL  C004 

ILLINOIS  BIOLOGICAL  MONOGRAPHS  URBANA 

2  1915-16 


3  0112 


017753341 


I''     V-  • 


■ .,'    '.'■'.'■^'  /.-''''«■  ' 


